The short answer
Raising fish fry rests on three pillars: protection from bigger mouths, the right tiny foods, and clean, stable water. Get those three right and most healthy fry will grow. The species barely matters — a guppy, corydoras or angelfish fry all need the same basics, just scaled to their size and mouth. This is where the real work of breeding happens.
Give them a safe space
Fry are eaten by adults, including their parents, so separate them. A breeding box inside the main tank works for a few; a dedicated grow-out tank is best for a batch. Add plants or moss for cover and security, and fit a sponge filter or cover the intake so tiny fry aren’t drawn in. Keep a heater running for steady warmth — see do I need a breeding tank.
Feed small, feed often
Fry have tiny stomachs and grow fastest on frequent small meals. Depending on size, use:
- Infusoria or liquid fry food for the smallest newborns (bettas, some egg-layers).
- Powdered fry food and crushed flake for larger fry like guppies.
- Baby brine shrimp — a superb growth food most fry graduate onto quickly.
Feed two or three times a day and remove leftovers. See what do I feed baby fish and our best fish food picks.
Keep the water pristine
Small, frequent water changes are the difference between fast, healthy growth and stunted or lost fry. Use dechlorinated, temperature-matched water and a slow, gentle refill. As the fry grow, thin the group so no one is crowded. For species-specific routines see how do I breed guppies and how do I breed corydoras, and browse aquariums for a grow-out tank.