Goldfish are Nutritious

[RD.]

This is more than crude fat and crude protein percentages, mineral and trace mineral dietary numbers. You are given that this is fish tissue which gives you an excellent idea of the amino acid profile and its digestibility.

The amino acid profile of fish tissue varies from species to species, if you can show me that goldfish have a superior amino acid profile compared to a food that has the bulk of its protein comprised from Herring, Antarctic Krill (Euphausia superba), and Squid, I'm all ears. The NRC's (National Research Council's) amino acid stats for the 4 most popular forms of fish meal, which include Herring meal, Anchovy Meal, Whitefish meal, and Menhaden meal, clearly demonstrate that not all fish are equal in crude protein, or amino acid content. The same applies to fatty acid profiles, the fact that a fat is unprocessed, does not equate to it receiving a gold label in quality.

BTW - I not only read the stats on goldfish & minnows from that paper you cited previously, I linked to it in the gar nutrition discussion that took place last year that I mentioned in my original comment. None of this is news to me, Rich.

Crude percentages of protein and fat on a feed label aren't very meaningful unless you know what the contents are. Even then you don't know the quality of the product. Fishmeal comes in different grades and freshness. We are talking whole, live fish and that is a lot of information in that statement. As for fat content, its fresh unprocessed fish oil. These are the gold standards in fish diets. We are not talking beef tallow, meat and bone meal, feather meal or dried blood. Its whole fish.

Now tell me something that I don't know. Again, this is old news. No one here is comparing bulk generic farm feed that may contain ingredients such as beef tallow, meat & bone meal, feather meal or blood meal, with goldfish, or anything else. There are commercial diets available in today's market that utilize nothing but the best of the best raw ingredients, those foods are simply not going to be economical for a commercial producer such as yourself. At a hobbyist level their costs are not a huge factor for most people that want the best overall nutrient levels that they can give their fish. Not just protein, and not just fat. Again, the only compromise that I see being made is that by the commercial farmer, who due to their large scale commercial applications must seek lower cost alternative feeds.

Yes, fish in general have a low tolerance for high carbohydrate diets. Piscovers are especially prone to diseases associated with high carbohydrate diets. There was a study in the Journal of The World Aquaculture Society (Vol. 33, No.4) where largemouth bass suffered serious liver damage and high mortality rates as a consequence of being fed a trout diet with excessive carbohydrate levels (>27%). I don’t know if you intended to make my case here for me or not.

I've been preaching against high carb inclusion rates in diets designed for fish for years, there is no argument there, but the inclusion rate of carbs can easily be controlled in a pellet feed. That my friend is entirely up to each manufacturer. The pellet food that I feed has a low carb content, and is in no way detrimental to the health of a piscivore.
I don't know anyone that keeps, or breeds piscivores such as Cyphotilapia frontosa, that feeds goldfish.

I disagree with you on this point. The bulk of feeders sold are merely fry. The balance of their free metabolic energy goes to tissue development. Not until fish exceed 100 grams will they begin to sexually mature and begin laying on fat stores. So while there will be some variation at the smaller sizes (aprox. 1 gram), I don't believe the numbers would range widely.

For a starter the proximate analysis that you are using for the foundation of your argument was based on the analysis of a single goldfish. No mention of species, size, weight, life stage, or anything else. Furthermore a fish does not have to be sexually mature to potentially have excessive lipid deposition. This would be highly dependent on exactly what & how much a goldfish is fed.

As an example;
http://www.tandfonline.com/doi/abs/10.1577/A03-035.1

A 12-week feeding trial was conducted to evaluate growth performance and hepatocyte changes in juvenile African cichlids Pseudotropheus socolofi and Haplochromis ahli fed commercial diets commonly used on cichlid farms in south Florida. Fish were fed either a trout starter pellet diet (TP diet; 52% crude protein, 17% lipid) or a mixed flake feed diet (fish flake [FF] diet) (47% crude protein, 7% lipid). For both species, growth was significantly greater (P < 0.05) in fish fed the TP diet than in fish fed the FF diet, H. ahli administered the FF diet exhibiting the slowest growth. The hepatosomatic index was not significantly different among treatments (P > 0.1). Histological examination revealed severe vacuolation of hepatocytes in P. socolofi fed the TP diet and moderate vacuolation in H. ahli fed the TP diet. Moderate vacuolation of hepatocytes was observed in P. socolofi fed the FF diet, and only mild vacuolation was found in H. ahli fed the FF diet. The lipid-rich TP diet may be suitable for commercial production of juvenile African cichlids up to 12 weeks of age, but prolonged feeding may result in excess lipid deposition and necrosis of the liver. Feeds like the FF diet, which produced slower growth but lower lipid deposition in livers, may be more suitable as a maintenance diet for cichlids in the home aquarium.

The fish used in this study were only 4 weeks old when the feed trial began, and averaged 0.06 g in weight, and 1.5 cm in total length.

The juvie H. ahli (S. fryeri) used in this study fared much better being a carnivore/piscivore, but it still showed a lipid accumulation in the hepatocytes. (<50%) The P. socolofi had extensive lipid accumulation when fed the TP diet.

This study came about after some cichlid farms in south FL suffered from some large mortalities in both 1998 & 1999. When the dead fish were examined they showed fatty infiltration of the liver, heavy vacuolation, and severe necrosis of the liver, pancreas, and spleen.

It was suggested to the farms that they replace ther feeds with one that had a lower lipid content (less than 10%) and supplement the feed with a vitamin premix. Clinical signs in the affected farms were resolved after implementation of these recommendations.

And I am somehow supposed to believe that a "goldfish" couldn't accumulate fat, when a juvenile carnivore/piscivore such as an S. fryeri did just that, in only 12 weeks.
Hmmmmmmm.


In my mind the entire thiaminase issue is a no brainer. When there are species of feeder fish that are known to not produce this B1 destroying enzyme, it seems rather obvious to me that one should go the safe route & feed those species, vs one such as goldfish that are known producers of thiaminase. As you said, at this point not much is even known about thiaminase, other than we do know that it has the potential to destroy B1.

Knowing that, why would one want to play Russian roulette with their fishes health, when safer alternatives are available? It makes absolutely no sense.

Unless of course one is simply looking for ways to gain support for a potential business venture of breeding/raising goldfish feeders.

 

[sjkoi]

Yeah, something like that. I took over an operation that grew feeder goldfish as we expanded our koi farm. I am familiar with their production since the first job I got in aquaculture was on a feeder farm. I am surprised at the vehement hatred directed at a food species that has been used in the hobby for decades. As I have said earlier in this thread I am taking the extreme view here and I don't actually believe that it is "best practice" to feed goldfish exclusively. I also though am highly skeptical of any canned diet no matter the cost or the quality of ingredients. Any dead food has problems. Pelleted food has even more. You have to cook the food under high temperatures and pressure which degrades the vitamin content. You then have to add in cereal binders and mold inhibitors and add back in the vitamins that were lost in production. Then the product begins to loose potency from the day it is manufactured. The product sits in a warehouse, and then in a pet store and then at home. How long was that since it was manufactures? How long was that since the ingredients were purchased to manufacture it? How long was that since the ingredients were harvested? Then we buy our fish food in bulk and online to save money. We buy the food that is discounted because we want to save money, but that is also the food that needs to be pushed out the door because it has been sitting at the store the longest. Once we open the bag then oxidation of the remaining vitamins accelerates even faster. Finally, when we place our pellets in the water the soluble vitamins begin to leach into our tanks. So quality, potency, cereal binders and other additives are all a concern with any canned diet. This is not news to anyone who is seriously in the hobby.

The number one thing I want from my efforts is good information so that I can make informed decisions going forward. I believe the "best practice" is to feed a varied diet of many species of fish and other items which also could include pelleted feeds only if you purchased the highest quality diet from a trusted manufacturer who pays top price for the best ingredients, and if it is purchased in small lots that are used quickly.

One area that intrigues me is the possibility that the hobbyist can produce their own diets at home for little to no cost that are superior or equal in nutrition to the best store bought brands. The gambusia minnow is easily produced. What about fly maggots and other good quality protein sources that could be produced at home using table scraps or other easily available ingredients like lawn trimmings or spoiled fruits and vegetables?

 

[Spiritofthesoul]

I like goldfish, they're pretty. They're just trying to make it in this world, cant we make it better for them? Goldfish may be a good source of protein blah, blah, blah....so are soybeans. Point is, we have MODERN alternatives. Better, high quality alternatives and our pets benefit from this. Should you only feed a dog raw meat? Would it hunt at In-n-Out if it were wild? Do we really want "wild"?
Just because you could doesnt mean you should and as far as a "treat" goes, get him a double-double...animal style.

My thoughts exactly.

 

[rup_pilot]

Frozen is far safer. I lost an 18 inch catfish due to feeding goldfish that weren't quaranteened. I used to get ich and it was a pain. I now only feed frozen silversides, pellets, and frozen raw whole shrimp. The only live food I feed is nightcrawlers. I get them at a bait shop and have never had a problem feeding them to my stingrays, gar, and knifefish. Since I stopped feeding goldfish, I haven't lost any fish and haven't had any diseases. My oldest fish is an 11 year old tinfoil barb. I also have a 6 year old knifefish and 8 year old gar along with several others.

 

[RD.]

Rich,

I don't see any vehement hatred being directed at anything.

You talk about "best science", yet so far you offer up none. Yes, there are manufacturers that make low cost feeds that have high carb content from terrestrial sources, poor vitamin & trace mineral content, and perhaps even low cost sources of protein such as feather meal. This too is not news to anyone who is seriously in the hobby.

There are also those that use nothing but premium raw ingredients, and extrude at what industry standards would be considered low temps, where the vitamin content of those raw ingredients is still largely intact at post processing.

"Amino acids, several vitamins, and inorganic nutrients are relatively stable to heat, moisture, and oxidation that occur under normal processing and storage conditions. Some of the vitamins are subject to some loss, however, and should be used in excess of the requirement."

(NRC Nutrient Requirements of Fish 1993)


I've seen post production nutritional analysis reports on the commercial pelleted fish food that I use, performed by non-biased 3rd party accredited institutions, and what you state simply isn't factual. You are using a very broad brush to paint a picture that clearly does not apply to all pellet feeds. You can be as skeptical as you like, but you have yet to bring any real "facts" to this nutrition discussion, just the ramblings of someone who seemingly wants to prove that feeder goldfish supply a better nutritional profile than all other types of feeds. You state that you want "good information" yet when that is offered you turn a blind eye.

The beauty of pelleted food is that a manufacturer can fine tune the nutrient profile of his feed to any level that he chooses. The fact that some manufacturers may fail in this area doesn't mean that we should throw out the baby with the bath water.

Let's use one common essential vitamin as an example, one that piscivores are not capable of producing themselves, one that must be supplied via the diet, Vitamin C.

A manufacturer can use raw ingredients that contain enough Vitamin C in just the raw ingredients of their formula to GREATLY exceed all minimum values that have been determined in any/all species of fish that to date have been studied in aquaculture circles. Just to toss out a number, let's use 400 mg/kg - in just the post production levels of the raw ingredients. A number that already greatly exceeds the "total" amount found in most farm feeds.

If a manufacturer have any concerns about potential bioavailability, nutrient levels, or potential loss during storage, they can then supplement with additional Vitamin C, very stable forms of Vitamin C, such as L-Ascorbyl-2-Polyphosphate. Not the highly degradable forms of the past, such as regular Ascorbic Acid. So just to toss out another number, let's say they add an additional 400-500 mg/kg of supplemental Vitamin C, the total Vitamin C content is now in the 800+ mg/kg range. (at post production levels)

Add that to a dense, extruded, sinking pellet, and the amount of Vitamin C loss when tossed into ones aquarium is minuscule, unless that pellet sits in the water for an extended period of time, which shouldn't be happening if one is feeding properly. If the food is eaten immediately, within a few minutes, that pellet will still contain the vast majority of its Vitamin C content, at a level that will exceed even the most high stress conditions that a fish may be placed under in an aquarium setting. If that feed is then stored properly, in a cool, dry, dark environment, the overall nutrient loss, including Vitamin C - would again be minuscule, unless that feed is being stored for several years.

You don't just open up a container several times and sudenly ALL of the vitamins go *poof* into thin air. The main concerns over the years about nutrient loss in pellet feed was due to many "farm feeds" containing only the bare minimum values, so yes in those cases nutrient loss in any form was something to be concerned about, for a commercial farmer.

And that's just one small example of how things can work if a manufacturer makes the effort to do things right. Most generic farm feeds are lucky if they have a fraction of that level of Vitamin C content intact at post production levels. Unless one is gut loading a goldfish with supplements immediately prior to feeding a piscivore, I'm guessing that the Vitamin C values of that food source would also be next to nothing.

And now you feel that it's possible that the average hobbyist can formulate their own feed at home for little to no cost that are superior or equal in nutrition to the best store bought brands. Are you kidding me? Of course hobbyists can supplement with minnows, maggots, meal worms, aquatic plant matter, etc, many already do - but that in no way equates to a well balanced nutritionally complete diet such as what is found in a premium pellet food. What you suggest is a shotgun approach to feeding, and the vast majority of hobbyists would have no idea as to the exact nutrient profile of their homemade food. By guess, or by golly! Can this work, sure, fish are very resilient creatures that can survive for years under less than ideal conditions, but superior ...... I don't think so. Most hobbyists don't even read labels closely, let alone understand the vast majority of it.

Your entire argument is based on a worse/best case scenario, as though ALL commercial foods are equal in raw ingredient quality, nutrient levels, production techniques, etc, and in your opinion "best" if one feeds live flesh/fat from ALL farmed goldfish. Right.

Sorry, but it's not that simplistic, nor is that a fair or even reasonable conclusion in today's market. You need to think outside of the box more, and forget about everything that you have learned or read 25 yrs ago about commercial farm feed manufacturing.

It's a new world out there Rich, welcome to the 21st century, and good luck with your feeder goldfish operation!

Over, and out!

 

[sjkoi]

Rich,

I don't see any vehement hatred being directed at anything.

You talk about "best science", yet so far you offer up none. Yes, there are manufacturers that make low cost feeds that have high carb content from terrestrial sources, poor vitamin & trace mineral content, and perhaps even low cost sources of protein such as feather meal. This too is not news to anyone who is seriously in the hobby.

There are also those that use nothing but premium raw ingredients, and extrude at what industry standards would be considered low temps, where the vitamin content of those raw ingredients is still largely intact at post processing.

(NRC Nutrient Requirements of Fish 1993)


I've seen post production nutritional analysis reports on the commercial pelleted fish food that I use, performed by non-biased 3rd party accredited institutions, and what you state simply isn't factual. You are using a very broad brush to paint a picture that clearly does not apply to all pellet feeds. You can be as skeptical as you like, but you have yet to bring any real "facts" to this nutrition discussion, just the ramblings of someone who seemingly wants to prove that feeder goldfish supply a better nutritional profile than all other types of feeds. You state that you want "good information" yet when that is offered you turn a blind eye.

The beauty of pelleted food is that a manufacturer can fine tune the nutrient profile of his feed to any level that he chooses. The fact that some manufacturers may fail in this area doesn't mean that we should throw out the baby with the bath water.

Let's use one common essential vitamin as an example, one that piscivores are not capable of producing themselves, one that must be supplied via the diet, Vitamin C.

A manufacturer can use raw ingredients that contain enough Vitamin C in just the raw ingredients of their formula to GREATLY exceed all minimum values that have been determined in any/all species of fish that to date have been studied in aquaculture circles. Just to toss out a number, let's use 400 mg/kg - in just the post production levels of the raw ingredients. A number that already greatly exceeds the "total" amount found in most farm feeds.

If a manufacturer have any concerns about potential bioavailability, nutrient levels, or potential loss during storage, they can then supplement with additional Vitamin C, very stable forms of Vitamin C, such as L-Ascorbyl-2-Polyphosphate. Not the highly degradable forms of the past, such as regular Ascorbic Acid. So just to toss out another number, let's say they add an additional 400-500 mg/kg of supplemental Vitamin C, the total Vitamin C content is now in the 800+ mg/kg range. (at post production levels)

Add that to a dense, extruded, sinking pellet, and the amount of Vitamin C loss when tossed into ones aquarium is minuscule, unless that pellet sits in the water for an extended period of time, which shouldn't be happening if one is feeding properly. If the food is eaten immediately, within a few minutes, that pellet will still contain the vast majority of its Vitamin C content, at a level that will exceed even the most high stress conditions that a fish may be placed under in an aquarium setting. If that feed is then stored properly, in a cool, dry, dark environment, the overall nutrient loss, including Vitamin C - would again be minuscule, unless that feed is being stored for several years.

You don't just open up a container several times and sudenly ALL of the vitamins go *poof* into thin air. The main concerns over the years about nutrient loss in pellet feed was due to many "farm feeds" containing only the bare minimum values, so yes in those cases nutrient loss in any form was something to be concerned about, for a commercial farmer.

And that's just one small example of how things can work if a manufacturer makes the effort to do things right. Most generic farm feeds are lucky if they have a fraction of that level of Vitamin C content intact at post production levels. Unless one is gut loading a goldfish with supplements immediately prior to feeding a piscivore, I'm guessing that the Vitamin C values of that food source would also be next to nothing.

And now you feel that it's possible that the average hobbyist can formulate their own feed at home for little to no cost that are superior or equal in nutrition to the best store bought brands. Are you kidding me? Of course hobbyists can supplement with minnows, maggots, meal worms, aquatic plant matter, etc, many already do - but that in no way equates to a well balanced nutritionally complete diet such as what is found in a premium pellet food. What you suggest is a shotgun approach to feeding, and the vast majority of hobbyists would have no idea as to the exact nutrient profile of their homemade food. By guess, or by golly! Can this work, sure, fish are very resilient creatures that can survive for years under less than ideal conditions, but superior ...... I don't think so. Most hobbyists don't even read labels closely, let alone understand the vast majority of it.

Your entire argument is based on a worse/best case scenario, as though ALL commercial foods are equal in raw ingredient quality, nutrient levels, production techniques, etc, and in your opinion "best" if one feeds live flesh/fat from ALL farmed goldfish. Right.

Sorry, but it's not that simplistic, nor is that a fair or even reasonable conclusion in today's market. You need to think outside of the box more, and forget about everything that you have learned or read 25 yrs ago about commercial farm feed manufacturing.

It's a new world out there Rich, welcome to the 21st century, and good luck with your feeder goldfish operation!

Over, and out!

RD,

I know it seems like the other side is closed off to the opposing argument, but that is not the case. I appreciate the counter points. There is a feed manufacturer who works closely with this site that I have the highest regard for and in my opinion makes some of the best fish diets for the hobbyist anywhere. I am painting with a broad brush in regards to commercially manufactured diets because a majority of them are insufficient as we both agree. If you would like to discuss a specific diet I’d be all ears. I am most familiar with diets developed for cyprinids and particularly koi. Koi are well adapted to accommodate commercial diets. I don’t advocate the feeding of live diets to koi for the hobbyist because the costs would be extreme, though they do very well on them. There is just not a critical need. Koi with their elongated guts are more capable of surviving off canned diets. At my farm I grow koi in mud ponds because of the ample natural nutrition available. In Japan they will stock as few as 10 fish per acre into ponds that can be up to three to four meters deep. Also prized fish are often returned to the mud to rebuild vigor after having spent extended time in a concrete pond on artificial diets. These fish are fed what are likely the most expensive fish diets in the world and still an artificial diet can’t match what nature provides in a mud pond. Koi farmers can make a decent living just renting their mud ponds to hobbyists looking to give their koi the very best during the growing season. When the weather cools off in the fall the koi are returned to concrete where they are housed in heated ponds, admired and fed throughout the winter until the very best are returned to the mud. I don’t know, but we are talking hundreds of years of tradition and experience here (21st, 20th and 19th century), fish that are worth in excess of $100,000 and they still have not found a substitute for the natural diet. That is the common carp, the diesel truck of the fish world, not these fast little piscivore sports cars we are talking about here. That is where I am coming from in regards to experience with commercial diets. In the koi world there is no argument on these points. We just wish our fish were so small that live foods were an option.

Public aquariums have realized the need to provide a natural and varied diet. Fresh fish is flown in from all over the world at great expense so specimens can have a nutritional diet that replicates their natural ones. AZA recognizes the value of using where possible food items that simulate natural feeding behaviors. For piscivores hunting prey stimulates appetite and simulates natural feeding behavior. Earlier a mention was made that fish fed live diets appeared to become more aggressive. That is likely. Among fish, and other species, the most successful members often become the dominant ones in a group. The AZA also recognizes the need for feeds that are economical, convenient and consistent. This is the argument for canned diets. However, it is more difficult to make a nutritionally satisfactory diet for piscivore fish than most other zoo species. I still maintain that there is not a canned diet on the market, at any price, that will match the nutritional value of live feeds. With some effort and ingenuity hobbyists could grow the bulk of their own diets in their backyards and garages with little expense.

I don’t claim to be a nutritional guru come down from the holy mount with tablets of stone. I have some years of practical fish keeping skills and ask a lot of questions. You say that I have not offered anything new here? I wish that were the case. If it is then this information has not circulated widely.

1) Goldfish and minnows are nutritious containing aprox. 59% protein and 9% fat.
- some variation on these numbers is likely from fish to fish

2) They contain a rich source of vitamins, minerals and trace elements.

3) There are no known cases where fish containing thiaminase have caused a thiamin deficiency in warm-water species when these fish were consumed live. Thiaminase is widespread and will likely be present in the tissue and gut of most wild fish. It has only been shown to cause nutritional deficiencies in some wild populations of cold-water species and to any species fed an exclusive diet of frozen fish containing thiaminase.

4) Diets rich in carbohydrates can lead to liver damage in piscivore fish.

5) Most commercial diets are ill suited for the needs of piscivores.
- however, there are some excellent high end diets that appear to be sufficient

6) Literature suggests that when feeding piscivores one should use a range of fish species (at least three) to ensure nutritional balance.

8) AZA recognizes the value of using both natural foods that stimulate natural feeding behavior and those that are economical, convenient and consistent in quality.

This is a large topic and we are just scratching the surface on the pros and cons of live fish as food. Nutritional value is unquestionably not a con here. It is disease introduction and health management in the tank that is the real concern. Once again I appreciate your counter point. I started this thread with a deliberately provocative post, but my true belief lies somewhere in the middle.

Rich

 

[sjkoi]

Frozen is far safer. I lost an 18 inch catfish due to feeding goldfish that weren't quaranteened. I used to get ich and it was a pain. I now only feed frozen silversides, pellets, and frozen raw whole shrimp. The only live food I feed is nightcrawlers. I get them at a bait shop and have never had a problem feeding them to my stingrays, gar, and knifefish. Since I stopped feeding goldfish, I haven't lost any fish and haven't had any diseases. My oldest fish is an 11 year old tinfoil barb. I also have a 6 year old knifefish and 8 year old gar along with several others.

Ding, ding, ding we have a winner. Disease in general, and Ich in particular, is the number one issue when feeding live fish. This goes for store bought or home grown.

 

[fishwhisperer]

disease maybe the #1 issue, but to restate your OP, "gold fish are nutritious" nutritious is to provide nutrition, substanance, energy. think about it this way... #1 combo at mcdonalds (BIGMAC!) provide nutrition, nurishment, and energy, but if i ate that for every meal every day i would die. period. end of story. look at a goldfish as u would a bigmac combo

 

[sjkoi]

I like goldfish, they're pretty. They're just trying to make it in this world, cant we make it better for them? Goldfish may be a good source of protein blah, blah, blah....so are soybeans. Point is, we have MODERN alternatives. Better, high quality alternatives and our pets benefit from this. Should you only feed a dog raw meat? Would it hunt at In-n-Out if it were wild? Do we really want "wild"?
Just because you could doesnt mean you should and as far as a "treat" goes, get him a double-double...animal style.

The ethics of working with livestock of any kind have always concerned me. I breed koi. Maybe 100 fish out of 1,000,000 hatched have any value. What do I do with the culls? I have used them as fertilizer. I also have tried feeding them to migratory ducks. Do I stop breeding koi because of the carnage of culling? Is that any different than what occurs in the wild? What about the few that are of quality to be sold as pets? Does their existence justify the ones that don't make it?

I also graze livestock on the banks of the ponds. I don't like to spray herbicides around the ponds. However, these animals will be sold for slaughter when they are older. That does not bother most. Are feeder fish any different? I don't know, but I have spent my entire life working in and around nature as an ecologist and fishery biologist. I know that life is what it is. We are afraid of death, but it is a part of life.

 

[RD.]

Rich,

In case you haven't figured it out yet I'm not some kid that just fell off of the back of a turnip truck.

Now you want to bring Koi into this discussion, as though plankton & micro-organisms found in mud ponds play some major key role in the growth & overall health of a Koi?

Champion Koi breeders have been feeding pellets for decades.

The reason that Koi show better growth & overall health in a low density outdoor pond is mostly due to water quality, not a natural diet. The water in Japan is very soft, very low in mineral content, and very low in buffering capacity, which makes keeping water parameters in a densely stocked indoor winter pond, much more difficult than in a lightly stocked outdoor pond with low TDS values. Not that it matters much in this discussion, but for anyone that's interested ......
http://www.northidahokoikeepers.com/sitebuildercontent/sitebuilderfiles/mike_snaden.pdf

But yeah, FREE food found in an outdoor pond is always a good thing, and certainly isn't counter productive to the health of a Koi. But let's not get carried away .....
Ask a large scale commercial Japanese Koi producer what their feed costs are over a year (tens of thousands of $$$- to hundreds of thousands of $$$), and it makes perfect sense as to why they farm their fish out to the outdoor ponds when temperatures permit.

As far as public aquariums etc, this is a site for hobbyists, not curators of public aquariums who who are custodians of species of fish that in many cases simply cannot be trained to eat pellets, or any type of prepared foods. Or are simply too MASSIVE in size to even consider pellet feed.

Yet when possible, many public aquariums do actually feed pellet food, a number of them feed the exact same pellets that I feed my fish. Imagine that!

Joe Yaiullo, one of the pioneers of reef keeping in the USA, and the curator/co-founder of Atlantis Marine World in NY has been feeding the exact same brand of pellets that I feed my fish, in his reef tanks for the past 10+ years. His 20,000 gallon reef set up is the largest in North America, and 4th largest in the world. Joe is one of the world&#8217;s most highly regarded Aquarium authorities. He has consulted with many public Aquariums worldwide, and has also presented reef-keeping lectures throughout the United States, Canada, and Europe.


Bob Fenner, who was previously mentioned in this discussion and who is widely known through his various published works on aquatics, as well as his wetwebmedia website, has not only singled out one brand of pellet feed as being a nutritionally complete food, but has gone so state that it is the best food, period. Bob has no vested interest in this brand of food, yet has seen enough first hand results of this product over the past 20 years to realize what can be achieved via a high quality premium pellet food, even with the most nutritionally delicate marine species found on the planet. Again, this is the brand that I feed my fish.

Charles Delbeek M.Sc., senior biologist at the Steinhart Aquarium in San Francisco also feeds these same pellets at their facility.

The list goes on & on, from public aquariums, to large scale breeders, to the average Joe Hobbyist.

Now factor into the equation that these pellets aren't even sold in commercial bulk sizes, a 5lb tub is the largest container that a public aquarium can purchase from the manufacturer. I think that it's safe to assume that public aquariums aren't going to the trouble of purchasing this food in 5lb pails, due to economics, or convenience. lol

But I'm not here to promote one brand, or even one type of food over another.
I'm just pointing out the flaws in your opinion, Rich, which for the most part is all you have really offered up.

BTW - just so there's no misunderstandings with anyone that reads this, while Goldfish may contain aprox. 59% protein and 9% fat, those numbers are listed on a dry matter basis. When fed on a wet basis, as in live feeders, 70-80% of what ones fish will be consuming, will be water. Now factor in the proximate values per ounce, pound, or whatever.

As far as goldfish containing a rich source of vitamins, minerals and trace elements. , IMO a more accurate statement would be that they contain a source of some vitamins, minerals, and trace elements, and are seriously lacking in many other essential vitamins, minerals, and trace elements, at least at the levels that I would personally consider to be ideal for the optimum health of a fish.
Would you like fries with that order of HITH?

While this discussion has been somewhat entertaining, I have no intentions of going round & round on the nutrient value of feeder goldfish.

I'm sure that at this point most members here can draw their own conclusions.

Cheers!