Swordtails

[Photoman]

Hi: I purchased 2 months ago a trio of swordtails. Beautiful fish from a breeder. The 2 females where pregnant. I put them in a tank separate from the male. One female dropped fry after a week. But after that no babies. The tank has floating plants as well as other planted ones. To have more babies should I put the male in? With guppies the female only needs to be pregnant once to produce a few batch of babies. Are swords like this? Thanks

[Diana]

I think swords are also like guppies, but given that she only had a couple of babies, perhaps she was pretty much out of sperm when she started developing those babies.

I would put the male in with the females. IME, in a well planted tank, quite a few babies will survive. If you do not want to risk it (adults eating the babies), then remove either the male of female when it is obvious she is pregnant. To move a pregnant female you can catch her with a net, but scoop her into a cup before exposing her to the air. Keep her fully supported in water during the move.

[Photoman]

Hi Diana, Sorry I took so long get back. I have the male with the females for 3 months. Nothing. I wonder if I should lower the temp of water when I do water changes? There is a lot of plants in the tank. If she had babies I should have some. What do you think?

[Diana]

Are the females getting fat? (Pregnant?) Maybe they do not like this male?
Is the male chasing them? The actual breeding take just a moment, easy to miss, but are you seeing anything that might look like it?

Swords can handle a very wide range of temperatures, I am not sure if there is an optimum temperature for breeding. I would avoid extremes. Mid 70s F is probably about right.

Are there any other fish in the tank? Most fish will eat fry, if there are any. Usually Swordtails do not eat their own young, especially if there is any sort of hiding places (it does not take much), but there are always exceptions. For whatever reason you might have a cannibalistic swordtail.

A few ideas:
Put the male and one female in a relatively bare tank where you can watch them. Plants etc are fine, sure can help. Just not so dense you cannot see what the fish are up to.
Once you have seen breeding behavior, remove the male. Allow the female to go through her pregnancy without any more chasing or anything. You could add more plants (guppy grass or other mid-tank filler) to help hide the fry. Continue watching the female. When she delivers, remove her and raise the fry in this tank.
If you suspect any of the fish are no longer fertile, then new fish might be the answer. Buy them from a reputable breeder, not from hatchery-raised store stock.

Here is more info about Swordtails:

http://www.seriouslyfish.com/species/xi ... -hellerii/