i have two fantails and they are about 2 years old. how can i tell if they are even male or female? they live in a small tank with lots of plants. the tank is about 3 times the size of a fishbowl. after they breed what do i do? i havent bred goldfish before.

Usually people suggest 20 gallon tank to breed. That probably is concerning about having enough space for them to chase around. I do not know how to tell a female from male by look. But if I see two fish chasing, I would pretty sure the one at behind is a male. The one at the front might not be female though. Anyway you can not help much about that since you have only two. Let's hope you have a pair to mate.

But after they spawn, you need to move the adult out of the tank. I hope you have prepared extra container for them. Then wait for 3-6 days, make a water change at the middle, fry will hatch out. You can wait for two more days for the fry to feed on yolk sac, then I would think it is better to scope all fry out to a fry tank. At that point the parents can return to their old home after a water change.

Good luck!

---Goldfishpal

If your tank is only 3 times the size of a fish bowl, it ain't big enough for 1 fantail, let alone 2 or more. Don't bother breeding until you have the correct set-up would be my advice, not fair on the fish.
Males normally are smaller than females. They also have breeding stars on their gill plates and leading edges of the pectoral fins.

I too, think you do have too small a tank. The rule of thumb is about 2 gallons per 1 inch of fish.

GP is right. Prepare a plastic bucket with water ready. If they spawn and you realize you have fertilized eggs, move the adult fantails to the bucket. Else they will eat them within a few hours.

Spawning usually take place in the early mornings. The chasing in a spawning is something best seen than describe. See the spawning video pinned at the top of the forum. The action is nothing like one fish chasing the other away one over territory kind of thing. It's more of a constant and persistant nuding from behind by the male fish to the female fish.

And if you do see eggs after the chasing. See if the eggs are translucent or opaque (white). Translucent ones are fertilized. Opaque ones aren't.

Watch out if there are too many opaque ones. They will be attacked by fungus if left in the tank. Then, you'll have to clean out the tank.

I hope that's enough information for you to start with.