I have to agree with you in principle regarding hybrids in the store. It is
hard to fish a nice purebred fish. There is definitely apprehension on my
part for doing it. In this case the store has tanks FULL of hybrid mutts.
For many fishkeepers, these fish are perfectly good pets. Unless you want
all identical fish, or completely diverse genus', they're going to breed.
And let us not forget, there is no creature on earth more loveable, more
loyal, than the mutt.


--
"The task is not so much to see what no one yet has seen, but to think what
no body yet has thought about that which everyone sees."

Schopenhaeur (1788 - 1860).


Two things could be happening. These fish are hybrids and the offspring
may have inherited different sets of genes from the parents. You could be
seeing natural variation in the hybrid offspring. Hybrids tend to have a
lot of variability.

Second, you could have simply stunted their growth by cramming WAY too
many in a 20 gal tank.

soapbox I'm personally not in favor of raising and selling hybrid fish.
I think it makes it harder to keep fish with clean genotypes in the hobby
for breeding and maintaining species that are hard to find in the wild.
/soapbox

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__ Elaine T __
__' http://eethomp.com/fish.html '__