Build the neon tetra school first, then select peaceful companions that share its water needs. Small adult size alone does not establish compatibility: predators, fin nippers and unsuitable water still rule out a combination.
Read the neon tetra care guide →Keep the school together instead of buying a few neons and several other schooling species. The examples use eight neons, leaving their group intact before adding a second species.
Each comparison uses a 20-gallon long with eight neons and one companion group. Leave a clear midwater swimming route, use cover around the edges and check the shared temperature, pH and hardness against your own water.
Each card is one separate example. The model’s result and the editorial guidance answer different parts of the decision.
A useful two-level starting point
A complete panda cory group adds bottom activity while the neons school above. Smooth substrate and deliberate bottom feeding matter; the corys are livestock with their own needs.
Example: 8 neon tetra + 6 Panda cory in a 20-gallon long.
No blockers or warnings in this example’s current checks. Individual behaviour and breeding still need your judgment.
Two schools, shared swimming space
Both groups occupy the water column. This comparison passes the model, but keep a clear swimming lane and recheck before adding a centrepiece or another school.
Example: 8 neon tetra + 8 Harlequin rasbora in a 20-gallon long.
No blockers or warnings in this example’s current checks. Individual behaviour and breeding still need your judgment.
Check your water before choosing
The dataset contains an overlap, but a broad species range does not mean every locally bred fish is acclimated to your water. Ask about the water they were raised in and avoid chasing a compromise with abrupt chemistry changes.
Example: 8 neon tetra + 6 Guppy in a 20-gallon long.
No blockers or warnings in this example’s current checks. Individual behaviour and breeding still need your judgment.
A fish sold small may grow large enough to eat a neon tetra. Check adult size and predation, not just the juvenile in the shop. Likewise, a temperature overlap does not make a crowded mixed school a good plan.
Compare complete communities by tank size →These examples start with eight neons. Keep a complete school before spending the available space on companions, and let tank dimensions and the full community determine any increase.
It may work in a suitable tank, but it is conditional on the betta’s behaviour. Read the betta companion guide and have a suitable separation option ready; an absence of model warnings does not guarantee peaceful behaviour.
No. A tall aquarium can add water without adding much swimming length. Check the exact footprint, adult sizes and total group before choosing more fish.
Original companion-selection guidance: curated-v0 (needs expert review), medium confidence. Model comparisons use data 0.3.0. Care values retain their field-level sources in the linked species profiles. These pages are not expert-reviewed compatibility guarantees.
Further reading from the neon tetra care guide
