Neon tetra

Water parameters

Tolerated range for this species. Aim for the middle of each band rather than the extremes.

Tank and habitat

Substrate: any.

Behavior

Plant interaction: plant safe.

Feeding

Small mouths limit food size. Micro pellets, crushed flake, and frozen daphnia or baby brine shrimp are staples. Frozen bloodworm is accepted but chop it first; whole bloodworms are too large for most neons to swallow. Feed small amounts twice daily rather than one large feeding. Neons are midwater feeders and generally ignore food that sinks to the bottom, so pair them with bottom feeders like corys to clean up leftovers.

Compatibility

• Stressed by aggressive or boisterous tankmates, even non-predatory species. Tiger barbs and serpae tetras cause constant fin damage.
• Classic community fish with corydoras, small rasboras, honey gouramis, and other calm species. Avoid anything large enough to eat them (angelfish will, despite being sold alongside neons in stores).
• Adult neons may pick at very small shrimp fry but ignore adult cherry shrimp and amano shrimp.
• Susceptible to neon tetra disease (Pleistophora hyphessobryconis), which is incurable and contagious. Quarantine all new neons for 2-3 weeks before adding to an established group.

Origin and habitat

Native to the western Amazon basin in southeastern Colombia, eastern Peru, and western Brazil. The true extent of the species' distribution remains unclear, though confirmed records exist from the area around Leticia/Tabatinga and tributaries of the Solimões, as well as the Río Putumayo. The type locality was given as "near Iquitos," Peru, though the original specimens came from an aquarium import. Described by George S. Myers in 1936 and named for American aquarist and publisher William T. Innes. Found in blackwater and clearwater streams with acidic conditions; the pH range spans roughly 4 to 7.5, with a preference for acidic blackwater. The bright iridescent blue stripe makes the fish visible to conspecifics in dark, tannin-stained water. One of the most widely kept tropical fish in the world, with roughly 1.8 million imported into the US each month, most from Southeast Asian farms; wild-caught fish also come from Colombia, Peru, and Brazil. Farm-raised stock tolerates a broader range of water parameters than wild fish. Average lifespan in aquariums is around 5 years with good care, though some specimens reportedly approach 10 years. Now placed in the family Acestrorhamphidae following a recent revision of American characins.

Breeding

Egg scatterer. Breeding in a home aquarium is possible but tricky. Requires very soft acidic water (pH 5.5, GH below 2), dim lighting, and a separate breeding tank with fine-leaved plants or spawning mops. Condition the pair with frozen food for a week. Spawning usually happens at dawn. Eggs are light-sensitive and the parents will eat them immediately, so remove the adults right after spawning. Eggs hatch in about 24 hours; fry are tiny and need infusoria for the first week, then baby brine shrimp. Most hobbyists never breed neons because the water parameters required are difficult to maintain, and commercially bred neons cost almost nothing.

Common problems

Neon tetra disease is the signature ailment: loss of color, cysts in the muscle tissue, erratic swimming, and eventual death. There is no cure and it spreads to other neons. Remove affected fish immediately. "False neon tetra disease" (bacterial) looks similar but responds to antibiotics. Ich is common in newly purchased neons that were stressed during transport. Quarantine and treat with heat (30°C for 3 days) or medication. Neons are sensitive to ammonia and nitrite spikes; they're often the first fish to show stress in an uncycled tank, which is why "my neons keep dying" is one of the most common beginner questions. The answer is almost always water quality.

Bioload

Further reading

• Why your angelfish ate your neons
• How bioload works
• Stocking ideas by tank size