Quick answer
How many neon tetras in a 15 gallon tank?
A standard 15-gallon tank (24 × 12 × 12 in, about 57 litres) holds about 7–10 neon tetras as the only fish, based on the bioload model behind our stocking calculator. If you add tankmates, keep the school towards the lower number.
Once you allow for a 5 cm substrate bed and some décor, a 15-gallon tank holds roughly 43 litres of water. Neon tetras are small, light-bodied fish with a low bioload, and they need to be kept in a group of at least 6. Our stocking model measures the combined waste of the school against the tank's water volume and footprint, and the 7–10 range keeps it at a comfortable 55–80% of capacity, which leaves room for a few snails or shrimp.
In a tank this size, keep any tankmates tiny: a few nerite snails, cherry or amano shrimp, or a small group of pygmy corydoras. If you add pygmy corydoras, reduce the neon school by two or three fish to keep the bioload comfortable.
Equipment for this tank: a filter delivering about 260 litres per hour of real flow (six turnovers an hour) and a 50 W heater to hold 24 °C in a typical heated room. Neon tetras do best at 20–26 °C in soft to medium water with a pH of 5.5–7.2.
Check it against your tank
Every tank is different. Enter your real dimensions and stock list to get a bioload-based stocking level, a filtration check and compatibility warnings for your exact setup.
Open the Stocking CalculatorFrequently asked questions
- How many neon tetras should be kept together?
- At least 6, and ideally 10 or more. Neon tetras are schooling fish: in small groups they become stressed, pale and more prone to disease, while a larger school is calmer and more colourful.
- Can I keep other fish with neon tetras in a 15 gallon tank?
- Yes, as long as the tankmates are small and peaceful. Avoid fish large enough to eat a neon, such as angelfish and most cichlids, and fin-nippers such as tiger barbs. Reduce the neon school a little for each tankmate you add.
- How many litres is a 15 gallon tank?
- A 15 US gallon tank is about 57 litres (15 × 3.785). A standard 24 × 12 × 12 inch tank measures about 57 litres from its outside dimensions and holds about 43 litres of water once substrate and décor are in.