Maximum fish sizes

[Moontanman]

I agree that experience varies greatly. If I recall correctly, there is a Korean Perch that someone on this board has that has outgrown it's documented "maximum" wild size.

I'm not saying it cannot happen I am saying that assuming a fish that doesn't meet this criteria is some how not being taken care of or is being kept in an inhumane manner is wrong. The things that make a fish get to it's maximum size are varied and many if not most are not under the control of the aquarist. On top of that being in captivity tends to dwarf fish and this dwarfing isn't an indication of less than optimal fish keeping. Different fish react to being in a tank in different ways. Different fish have different genetic make up. Look at the spectrum if humanity, all the same species but lots of people raised under ideal conditions attain different statures. It's that same for fish, many things not under our control can define the eventual size of a fish. Most will never approach maximum size in captivity or in the wild. sometime the maximum size fish is a freak, like the worlds record LMB, it was a sterile freak that had never been stressed by the hormones regular fish under go seasonally. What we should expect is a fish that is healthy and that lives for a reasonable life time. I've had Cardinal tetras live more than 6 years but they were not as big as some I've seen but their life span would indicate health. Life span should be the marker not size.

 

[chrisdef15]

On top of that being in captivity tends to dwarf fish and this dwarfing isn't an indication of less than optimal fish keeping.

Where is that from? While its possible some fish get "dwarfed" in captivity as has already been said most get bigger if looked after well. Look at the African Cichlids you will be lucky to find many mbuna ect in the wild over 5-6" but its not uncommon for them to be 8" in captivity. Alot of small fish especially like tetra's guppies platys ect get bigger too because there is plenty of food and nothing to eat them. Just a guess ofcourse but ide say the big guys could get bigger then ones in the wild too but 90% of ppl dont have the tanks for them.
But i do agree the numbers thrown around are usually records and not an average of the whole species.

 

[cchhcc]

If you are keeping a fish and expect it to not reach the average size of its wild counterparts you are doing a great disservice to the fish and are bordering (at best) on animal cruelty................... IMO of course!

 

[TwistedPenguin]

I read awhile back about the different pheremones (bet I spelled that wrong) that fish in home aquaria give off. A dominant fish gives off the pheremones and the less dominant fish doesn't grow as much. It probably wouldn't happen in the wild because they're not in as close proximity as they are in tanks.

 

[benzjamin13]

I read awhile back about the different pheremones (bet I spelled that wrong) that fish in home aquaria give off. A dominant fish gives off the pheremones and the less dominant fish doesn't grow as much. It probably wouldn't happen in the wild because they're not in as close proximity as they are in tanks.

I read this too. They say that it prevents them from outgrowing their surroundings, but it also stunts them. So when people say, "It'll only grow as big as it's tank" It's somewhat valid, but it's not good in anyways.

 

[Moontanman]

If you are keeping a fish and expect it to not reach the average size of its wild counterparts you are doing a great disservice to the fish and are bordering (at best) on animal cruelty................... IMO of course!

If you had read my post you have seen I said maximum size not average size. Average size is what we should look for in most fish. the really large ones probably won't see that and a few of the smaller ones might actually get a bit bigger than average. But to say that a fish that doesn't achieve maximum size is being treated cruelly is way off the mark. Fish achieve the size they do from genetic inputs, inputs of day length, pheromones, food quality and availability and simply from the stress of captivity. If a fish doesn't become deformed or sickly reaching some ideal of maximum size shouldn't be thought of as necessary. As I have said before even perfect conditions will not always result in a maximum sized fish. In the wild only a few fish will approach the maximum for that fish. to assume we have been somehow cruel or have mistreated a fish that doesn't reach maximum size is more than a little ridiculous. I bought a pangashius shark (sp) from a pet shop that had been kept in a too small tank and was dwarfed. I tried to get it to grow bigger but it never did. It never got over 12" or so even though it was kept in a 125 in the winter and a 800 gallon pond during the five or six months of summer we have here. It was finally eaten by a bird of all things one day while I was at work. It was a beautiful fish, it knew me and would come to eat from my hand. I got a lot of enjoyment out of it over the seven years i had it and it was just as active and "happy" as any other captive fish i have ever had. If keeping a fish that doesn't reach maximum size is cruel then keeping big fish at all is cruel. No way you can really provide the environment even close to the wild for a big fish and we would be very hard pressed to even provide the bare necessities for a cardinal tetra much less an Oscar. So either it's ok to keep these fish that do not reach maximum size or it's not ok to keep any of them.

 

[Moontanman]

I read this too. They say that it prevents them from outgrowing their surroundings, but it also stunts them. So when people say, "It'll only grow as big as it's tank" It's somewhat valid, but it's not good in anyways.

How can anyone assume that the size of a fish somehow decides how well it was kept? If you took a human baby and raised it in a 40 by 40 room I have no doubt it could grow to maximum size but would raising a human in such a small space really be ok just because he reached maximum size? Fish are a whole lot more flexible than humans or lets say mammals in their final size. Like all cold blooded animals temps, available space, and food supply play a huge role and the result is not an animal that lacks anything. In the wild fish are often dwarfed for various reasons. It's all they know and they do not die off or other wise show any signs they are some how unhappy with their environment. Size is not a justifiable criteria for judging how well a fish is kept. there are limits of course, a pacu couldn't be kept at a silver dollar size it's whole life but expecting it to have to be three feet long (or however big they can get) isn't and shouldn't be a requirement for this fish. a fish that is truly not treated correctly will be deformed and skinny, unhealthy and short lived. size doesn't necessarily figure into it. The condition of the fish should be what it is all about.

 

[Bre]

This is a very interesting read!!!!!

 

[cichlid2006]

the fact the fish MAY reach a potential size should be catered for. as an example, a common size may be 8-10" but it may have the potential to hit 12" so the 12" must be catered for IMO. if you buy a tank large enough to house only 8" of fish you will have to buy another tank to accomodate the max size if it reaches that.
not using max sizes is asking for trouble IMO.

 

[cchhcc]

How can anyone assume that the size of a fish somehow decides how well it was kept? If you took a human baby and raised it in a 40 by 40 room I have no doubt it could grow to maximum size but would raising a human in such a small space really be ok just because he reached maximum size? Fish are a whole lot more flexible than humans or lets say mammals in their final size. Like all cold blooded animals temps, available space, and food supply play a huge role and the result is not an animal that lacks anything. In the wild fish are often dwarfed for various reasons. It's all they know and they do not die off or other wise show any signs they are some how unhappy with their environment. Size is not a justifiable criteria for judging how well a fish is kept. there are limits of course, a pacu couldn't be kept at a silver dollar size it's whole life but expecting it to have to be three feet long (or however big they can get) isn't and shouldn't be a requirement for this fish. a fish that is truly not treated correctly will be deformed and skinny, unhealthy and short lived. size doesn't necessarily figure into it. The condition of the fish should be what it is all about.

The simple fact that almost no one on these kind of sites ever raise their predators to anything approaching full (i.e. average) size is a sign that proper conditions are not being provided. For instance, look in any fish market or fishing lodge in Central America, and you'll see just how large dovii can grow. Similarly, you can reel in P-Bass one after another when fishing in the Amazon basis that dwarf anything you seem to see in almost any private aquarium. Stunted grow is very definitely an unhealthy side effect of a less than ideal habitat. Any curator at a zoo or public aquarium will confirm that fact.

On the flip side, some fish actually grow larger in the aquarium than they do in the wild. Availability of food of a more nutritious profile and lack the of predation are usually the reasons. Members of the Mbuna group who normally feed on algae/aufwuchs grow much larger in aquaria after being fed nutrient dense foods.

It is not a complicated matter to provide what is necessary for full growth. Fish farmers do it all the time. The problem lies in being realistic with yourself when you acquire a fish. There are hundreds (thousands) of people on these sites that acquire fish that will never be truly provided what they need.