So _female_ fish have the protusion near the base of their anal fins? I guess I'll hafta re-name Jim Beam then... do you sex an Oranda the same way? I dont see any obvious protrusions on what-I'm-assuming-is-a-him, but then again my Commet keeps vying for my attention when I'm trying to get a good look.... just curious, thanks!

Boys have an inny butt and the girls have the out butt.

Also when its breeding time the boys will get tubercles on there front fins and all over there gill plates.

Anther thing is normally girl fish are more rounder in shape and the males are more stream line looking

koko, when a female fish is mature enough to breed, will she always have an outy or only when she is in the mood? i want to get a male bubble eye so i can breed cos i managed to pick up 3 girls the other day and was wondering if there were any sure ways to tell when they are in the tank of the petshop other than the chubbiness, tubricles and innies?
thanks!

Here's a pic to help out.

That pic is very helpful!! I'm now afraid to look at my fish, I just couldn't rename them at this point! So how old does the male have to be before he gets tubericles?

about 2-3 years

There toosh always will be the same, they wont change at all in there lifes. but some times its really hard to tell in the younger fish

Does this acount for koi too?

Wow. If that picture doesn't define sexing then I don't know what does!! (those are some big fishy!! )

So I have a sort of related question. I have no idea how old my fish are. I mean, I got them from pet stores when they were small 1-2 inches I guess. So how old were they then? Is there like a general "fish aren't sold until they're at least such-and-such age?" rule?

thanks.

well, all the petshops ive been to only have them from about 1 year onwards. im not sure if there is a rule but they are a bit unstable any younger than that so i think it would be a bit pointless before that, theyd lose a lot of money i think. hope this helps you out a bit!

so, hold on, it looks like in the pic that the males port is futher away from the anal fins than the female, am i right?

At least the angle it was taken, Yes.