Can 2 baby betta fish be put together?

The first few days or so they can be kept with the male - which is the one that tends to the nest, not the female - but you must remove them afterwards else the betta can mistake them for food. Since females do not tend the nests they are more likely to eat their fry, however on some rare occasions they will tend to the nest too, but it is not common.

You shouldn't leave the female with the fry, the females kill the fry when they are hatched, that's why the male kills the female after the spawn. It would be best if, when spawning, you keep the female in a breeder or a tall glass in a 5 and more gallon tank. When the male is finished with his bubble nest take the female out so they can do there magic, which really means the male squeezes the eggs from the females body. You have to make sure the female isn't too small or he could kill her. And after that you should but the female in a tank so she can recover. Leave the the male with the fry (baby fish) for 2-4 days after that remove him. When the male fries get older they tend to be aggressive and larger, it would be best if you put the fries in a large cup each so you don't risk one fry killing its sibling. BUT if you single out the males only the female fries should live in peace for a while unless they are as aggressive as a male. I hope i helped you =D (please do not delete)