Interesting read for those who feed fish multiple times a day

[Modest_Man]

I feed sinking foods more (not 100%, just more than floating) just based on my observations with trout in the wild mostly. How much of their diet floats along on top of the surface? Not much. You can catch fish on dry flies, sure, when there is a hatch going on but you can catch fish year round using a subsurface pattern emulating a nymph or a larva (bigger fish too, if you eat off the surface all day you're an osprey meal). For a week or two after stocking you can catch planted hatchery trout off the surface one after another, after a couple weeks they key in on wild foods and it's much more of a subsurface game.

Sinking food also makes the fish work harder for their meal, it gets down in the gravel and fish need to do more "grazing" type feeding than just sucking down 10 floating pellets in 1 minute. Spreads the consumption out a bit. Same reason why I mention smaller pellets. The fish has to work harder and longer (expending energy) for an equivalent amount of energy (50 sinking 1mm pellets vs. 2 4.5mm floating pellets).

 

[Modest_Man]

Cyphotilapia frontosa (23Æ9–266Æ0 g) showed high variability in the mass–gut length relationship, likely due to development of a large nuchal hump as adults.

I found this statement interesting. Too bad they don't explain that at all. That also gave the authors enough indication of C. frontosa being a part of a different population (along with B. microlepis) to eliminate them from the study (as they were outliers).

The nutrient content, energy content and digestibility of food resources all influence the overall quality of an animal’s diet. As these components of food quality are often correlated (e.g. low-nutrient, low-energy, high-fibre plant material vs. high-nutrient, high-energy, easily-digestible animal tissue), their relative influences on intestine length are difficult to separate. Our use of stable isotopes as a proxy for diet focuses on nitrogen that is assimilated, thereby emphasizing dietary material that is digestible. However, there may be considerable variation in the ease of digestion of items that have similar nitrogen isotope ratios. For example, although scale-eaters and piscivores both feed high on the food chain, scales are presumably more difficult to digest than muscle, and scale-eaters may therefore require a longer gut for the extraction of necessary nutrients and energy from their diet. Such differential digestibility of food resources may have contributed to variance in intestine length that was not explained by isotopic trophic position. Indeed, scale-eating fishes appear to have longer intestines than do piscivores of roughly equivalent trophic position.

Found this interesting as well.

Second, intestinal plasticity has been demonstrated experimentally in perch (Olsson et al. 2007), prickleback fish (German et al. 2006) and Tropheus (P.McIntyre and Y. Vadeboncoeur, unpublished data), and observations in LakeMalawi cichlids suggest shortening of the gut in mouthbrooding females that are unable to feed regularly (Reinthal 1989). More generally, plasticity in internal organs in response to environmental stimuli has been documented in many vertebrates (reviewed in Piersma & Lindstrom 1997; Starck 1999), including fasting snakes (Starck & Beese 2002), migrating birds (Karasov et al. 2004) and rodents in fluctuating environments (Naya, Bozinovic & Karasov 2008), and the physiological mechanisms underlying gastrointestinal plasticity are well understood in several taxa (Starck 2003). Thus, we believe that the observed variation in T. brichardi intestine length is a largely plastic response to differences in the nutrient content of their algal diet.

Learn something new every day. You're right Neil, I did not read the paper before posting and made the assumption that gut length was genotypic instead of phenotypic in nature. I apologize. No where though did I see the paper mention a phenotypic change of 50%. Can you point that out for me? I'll also point out that the study had a very small sample size (n = 4) for each area, which could lead to some different results if repeated.

Too bad the diet manipulation experiment by P. McIntyre&Y. Vadeboncoer is unpublished...I'd like to read it. Guess I'll go look up the one on perches or pricklebacks.

http://onlinelibrary.wiley.com.prox....edu/doi/10.1111/j.1095-8312.2007.00742.x/pdf

http://www.springerlink.com.proxy.library.oregonstate.edu/content/y3047476673l0166/fulltext.pdf

 

[aclockworkorange]

Sinking food also makes the fish work harder for their meal, it gets down in the gravel and fish need to do more "grazing" type feeding than just sucking down 10 floating pellets in 1 minute. Spreads the consumption out a bit. Same reason why I mention smaller pellets. The fish has to work harder and longer (expending energy) for an equivalent amount of energy (50 sinking 1mm pellets vs. 2 4.5mm floating pellets).

I actually like the floating pellets for larger fish. I just find it cleaner and easier to judge exactly what they're eating and don't have any issues with a pellet or two getting under wood or a rock or getting sucked into a filter intake. I think that extra amount of energy used that you're referring to is pretty negligible.
I also think a lot of fish keepers don't have enough current flowing in their tanks and simply just overstock and go for minimum tank size which compounds the whole lack of energy used issue.
Also, I don't think your math is right on the 50x1mm pellets equaling 2x4.5mm pellets.



Sent from my iPhone using MonsterAquariaNetwork app

 

[aclockworkorange]

I also find a lot of larger CA cichlids to be less actively grazing than juveniles (depending on the species of course!). I think it may be related to the larger fish being able to take larger prey items in the wild.

Here is something interesting on that topic:

That is a freshly wild caught argentea. I think by any of our standards that that fish is a bit overweight. I think he must have found a nice isolated area where livebearers or something came to breed and was just horking them back.



Sent from my iPhone using MonsterAquariaNetwork app

 

[RD.]

Not much of anything that we do in our glass boxes imitate what takes place in the wild, so IMO whether a fish eats from the surface or below the surface doesn't have a whole lot of bearing in this discussion. (overfeeding) Some fish feel more comfortable eating from the surface, some seem to prefer sinking foods. Not that there's anything wrong with your method, but I wouldn't consider pellet types being part of the golden rule of feeding fish.

Not trying to nit pick, I completely agree with the rest of your points in that comment.

•Feed less than you think necessary
•A couple times a week skip feeding entirely
•Feed smaller pellets

I see people feeding 10mm pellets to fish that are 6", I can only assume it's in the misguided belief that by doing so it will speed up the growth in their fish? Or feeding "high protein" foods, when their fish are fully mature. Again, it defies everything we know about the nutrient needs of adult cichlids, but it seems to be a common theme among many MONSTER fish keepers.

Sinking food also makes the fish work harder for their meal, it gets down in the gravel and fish need to do more "grazing" type feeding than just sucking down 10 floating pellets in 1 minute. Spreads the consumption out a bit. Same reason why I mention smaller pellets. The fish has to work harder and longer (expending energy) for an equivalent amount of energy (50 sinking 1mm pellets vs. 2 4.5mm floating pellets).

It has nothing to do with nutrition, and everything to do with spreading the feeding out.

It really depends on the fish, and how one feeds them. From a nutritional stand point I want my fish to consume pellet foods very quickly once those pellets enter the water column, to avoid water soluble nutrient loss. When using floating pellets, I feed only one or at the most two pellets at a time (depending on the size of the fish) moving from one tank to the next. I also break up their daily intake into two small feedings, one in the AM, and one in the PM. By doing so I am spreading out their overall consumption at any given time. Once a fish matures I only feed once a day at most (1 small feeding) with days within the week where no food is offered.

Also, as Jeff just mentioned using floating pellets I can control exactly what each fish consumes, with no concerns about any food getting lost within the substrate. A couple of my tanks contain rather large rocks/gravel, so in those tanks floaters make far more sense.


IMO the key point to be taken away from that previous paper that I linked to is this.

The nutrient content, energy content and digestibility of food resources all influence the overall quality of an animal’s diet.

Something that I have stated time & time again on this forum. Some of today's commercial foods are far more nutrient dense, have higher energy content, and far greater overall digestibility than foods manufactured 30 yrs ago. One can feed less, and overall nutrient wise get far more bang for your buck.

The trick is finding the sweet spot for each fish, based on their age, size, energy level, etc. Two fish of the same species, age & size, can require a vasty different amount of feed based soley on each fishes overall energy level in an aquarium. Some fish are laid back & mellow, some are hyper aggressive & never stop moving.

Learn something new every day. You're right Neil, I did not read the paper before posting and made the assumption that gut length was genotypic instead of phenotypic in nature. I apologize. No where though did I see the paper mention a phenotypic change of 50%. Can you point that out for me? I'll also point out that the study had a very small sample size (n = 4) for each area, which could lead to some different results if repeated.

Hey, no problem. I assumed that you hadn't read it when you posted. I don't believe that I stated that the paper linked to mentioned a phenotypic change of 50%. The 50% data came from an unpublished study performed years ago. I have no idea how many generations removed from the wild those "domestic" Tropheus were.

My point was simply that even among wild cichlids, they can quickly adapt to whatever food source is readily available.

 

[RD.]

That is a freshly wild caught argentea. I think by any of our standards that that fish is a bit overweight. I think he must have found a nice isolated area where livebearers or something came to breed and was just horking them back.

LOL, I was wondering if you would post that pic. I agree, that fish must have had a constant high energy food source, and he was probably several years old when that photo was taken. I certainly wouldn't be complaining if that fish was swimming in one of my tanks, slightly overweight or not.

 

[aclockworkorange]

LOL, I was wondering if you would post that pic. I agree, that fish must have had a constant high energy food source, and he was probably several years old when that photo was taken. I certainly wouldn't be complaining if that fish was swimming in one of my tanks, slightly overweight or not.

Hey, me too, but I'd put him on a diet for a bit.


Sent from my iPhone using MonsterAquariaNetwork app

 

[Modest_Man]

Also, I don't think your math is right on the 50x1mm pellets equaling 2x4.5mm pellets. [/url] app

mm is the diameter...not a linear relationship between diameter and mass! So for length yes my numbers don't add up but for mass it's more reasonable. Though you're right I just grabbed some numbers. I feed both floating and sinking.

The perch article was pretty interesting, especially the part where they swapped fish from one diet type to another and there was a period of adjustment where the fish degraded body wise before getting used to the new diet.

 

[clekchau]

wow i think i feed too much i feed twice a day and skip 1 day a week, the fish are not fat though, just right in my opinion.

so once five days a week and skip 2 days is good?

 

[tableau]

Very interesting. How much is too much ? I know it depends on many factors (fish activity level, age ...), but could you guys tell me how much you feed your fish. I have heard the size of the fish eyes, but concretely... I personnaly feed my 5.5 iches female dempsey (1 year old) 50 1mm NLS pellets two times a day. The fish is not fat at all. I would like to compare with experienced fishkeepers.