Peaceful in Every Direction
A neon tetra is peaceful past the point most fish manage: it carries no aggression toward tankmates, no fin-nipping, no territorial claims — nothing but the schooling instinct and an appetite sized for crumbs. Neons do not even compete properly; at feeding time one darts forward, takes a fragment of flake and falls back into the cloud. In a community aquarium a neon school is pure decoration and calm, the residents least likely to cause a problem in any month of the tank's life. Every compatibility question asked about neons is really a question about what might be done to them.
Their Safety Is Decided by Your Stocking List
A neon grows to barely an inch and a half, built like a bright mouthful, and in the wild it is exactly that — standard prey for the angelfish whose rivers it shares. Inside glass the same arithmetic applies: any fish that can fit a neon in its mouth eventually will, usually at night, one at a time, until the school that seemed fine for a month quietly halves. This is not malice and it cannot be trained away; it is the single most common way beginners lose neons, and it is decided entirely by what else you choose to stock.
Tankmates That Share a Neon's World
The safe companions are the small and the gentle: other little tetras and rasboras, corydoras working the floor beneath the school, a honey gourami floating above it, otocinclus and cherry shrimp along the bottom and the glass, and snails, which are beneath a neon's notice entirely. In this company neons school openly all day, and the school itself — ten or more strong — is their main defence, keeping their confidence high and their colour at its electric best. A community built entirely at their scale is also the easiest to feed, since every mouth in it is small.
Fish That See a School as a Larder
Angelfish are the classic mistake, sold small and sweet in the next tank to the neons they will eat once they reach adult size. The same applies to larger cichlids, big boisterous barbs, predatory catfish, and any fish whose mouth gapes wide enough to suggest the outcome — if a neon fits, assume a neon goes. Even mid-sized fish that never swallow one can stress a school into hiding and missed meals. When in doubt, judge a proposed tankmate by the size of its adult mouth, not by its shop size or its first month of good behaviour.
Feeding Small Mouths in a Busy Tank
Neons eat delicately, and in a mixed tank they can be outpaced: crush flake down to fragments, scatter it widely across the surface so the whole cloud can rise and feed together, and confirm over the first weeks that their bellies stay gently rounded. Their colours amount to a daily report card — luminous in a settled, well-fed school, washed out whenever something in their world is wrong. Keep a simple record of the school's numbers, any losses and your regular water readings as the tank matures, and their Pet Passport on KinsLe holds that history in one packet, ready for the day you need advice about them.