Baby fish, or fry, are considered grown when they are able to fend for themselves at approximately 4 to 6 weeks, depending on the fish's environment and diet. At this time, the baby fish can be introduced into a common tank.
The healthy adult female fish can give birth to baby fish every 4 to 8 weeks, depending on their diet, water conditions and temperature. When a fish is ready to give birth, move her into a separate 5 to 20-gallon breeding tank. Once the fish release the fry, remove her from the breeding tank. When the fry have outgrown the risk of being eaten, around 6 weeks, they can be introduced into the common tank. Feed the fry baby fish food, baby brine shrimp or crushed quality flake fish food.