The short answer
Not always — but a breeding tank is the most reliable way to raise fry. Whether you need one depends on the species and how many babies you want. For a few livebearer fry, dense plants or a breeding box inside your main tank can be enough. For egg-layers, bettas, or a whole batch you actually want to grow out, a separate tank makes all the difference.
When you can skip it
You can often manage without a dedicated tank if:
- You keep livebearers and are happy with the handful of fry that survive in a heavily planted community tank.
- You use a breeding box — a mesh trap that hangs inside the main tank — to protect a pregnant female or a small number of fry from adult mouths.
This is the low-effort route, and for casual guppy keepers it’s usually fine. See what do I do with baby fish.
When you really need one
A separate breeding or grow-out tank becomes important when:
- You’re breeding egg-layers like corydoras or angelfish, whose eggs and fry are eaten fast — see how do I breed corydoras.
- You’re breeding bettas, which need controlled, supervised conditions — see how do I breed bettas.
- You want to raise a full batch to a decent size rather than a few survivors.
Setting one up
A modest tank of 20–40 litres, a heater, a sponge filter and a plan for frequent gentle water changes covers most fry. Cycle it first so the water stays stable — see how to cycle an aquarium. A nano aquarium works well, and you can browse all aquariums here. For raising the fry once it’s ready, see how do I raise fish fry.