How long until you can put your baby platies in with the adults?

Answer 1

The reason for isolating baby fish from adults is that most adult fish consider fry to be snacks. When the baby platys are too big to fit in the biggest mouth in the aquarium, it's safe to put them in. Remember that the biggest mouth may not always belong to the biggest fish!

If the biggest fish in the aquarium are adult platys, when they're about 1-1.5cm long (around half an inch) they're big enough. They'll probably reach this size after about a month, provided the water is warm and clean and they're fed high quality food.

The other consideration is feeding; if you put baby fish into a tank with adult fish and your main food source is pellets, they may not get enough to eat, so make sure you use some flake food until they get bigger. (If you normally feed flakes, this isn't a problem.)