fry massacre

Question
QUESTION: I am sitting here bawling my eyes out.
this morning before work, I saw a baby fish swimming in my tank. It confirmed my suspicions that my swordtail was pregnant. I immediately put her in a breeder's box inside the main tank.

upon returning to work, she had delivered over 30 baby fish. yes, some were already dead.

I transferred them to their own tank.

I just checked on them.

every single one of them is dead.

I'm so upset. I murdered my baby fish before they had a chance to live. is it because I transferred them to their own tank? should I have left them in the breeder box? I thought I was doing good.

apparently I didn't.

I feel so horrible and can't stop crying.

ANSWER: Hi Desirai

Don't be too hard on yourself. You did exactly what you thought was best and everything you knew to protect them. When it comes to baby fish born in captivity, only the strong survive. You will likely lose many each time, despite what you do to help them.

However, you did make a couple of mistakes.

First, you should not have moved the mother fish into the breeder box. That is for the fry to protect them from the other adult fish in the tank. The mother should remain in the main tank as putting her in a breeder box can stress her out and she will abort the birth. In this case, it sounds like she didn't do that.

Next, you should not have moved the fry to a different tank. They were not near strong enough to handle that type of transition. When you notice baby fish in the tank, put them in the breeder box. If you have to leave, you can put some floating plants or Java moss in the tank for the fry to hide in until you can get home to rescue them.

She will likely have many more. Swordtails will have anywhere from 25 to 100 fry. They can also have fry for up to 6 months after one mating. So now you're a little more prepared in the event she does have more.

I really hope I've been helpful to you, good luck!

Richard

---------- FOLLOW-UP ----------

QUESTION: thanks..... I'm trying to not think about it right now.

all the fish I have in my tank are female except for a male platy. could the male platy of fathered the babies? can platy and swordtail breed? I think I read that swordtails are some sort of a platy.

I have in my tank 1 swordtail, 1 platy, 1 female betta fish, and 2 cory catfish. and a snail that is MIA.

Answer
Yes Swordtails and Platys will mate. Or, depending on how long you've had her, she could've been pregnant when you bought her. Gestation period is from 28 to 30 days (about a month). But the time she is likely to give birth is difficult to predict because female swordtails can store sperm, so she can give birth multiple times even if there is no male around.