Neon Tetra
The world's most popular tetra — a living jewel with an electric blue stripe that glows under aquarium lights. That neon-blue lateral line, that ruby-red tail flash, those perfect synchronized schools. Complete guide: the Neon Tetra Disease (NTD) that has NO CURE, why they need soft acidic water, and why a group of 6 is the absolute BARE MINIMUM.
📋 Species Overview
🐠 The Schooling Imperative — 6+ MINIMUM, 10+ IDEAL
Neon Tetras are obligate schooling fish. In groups under 6, they become stressed, hide constantly, lose color, stop eating, and die prematurely. A group of 10-15+ creates the mesmerizing synchronized swimming they're famous for. In a 10-gallon, keep 6-8. In a 20-gallon+, keep 12-20. Cardinal Tetras (Paracheirodon axelrodi) look nearly identical — the red stripe extends the full body length instead of stopping halfway. Neon = half-red, Cardinal = full-red.
⚠️ Neon Tetra Disease (NTD) — No Cure
Neon Tetra Disease (NTD) is a sporozoan parasite (Pleistophora hyphessobryconis) that's incurable and always fatal. It's the #1 killer of Neon Tetras in home aquariums. Symptoms: fading/loss of the neon blue stripe, white patches in the muscle tissue, curved spine, restlessness at night, emaciation, and death. There is NO TREATMENT. Remove affected fish immediately and euthanize — the parasite spreads when other fish eat the dead body. Prevention: quarantine ALL new fish for 2-4 weeks, maintain pristine water quality, and buy from reputable sources.
🏠 Tank Setup
- Soft, acidic water: pH 5.5-7.0, GH 2-10 dGH. In hard alkaline water, Neons survive but don't thrive — they're more susceptible to disease
- Blackwater setup ideal: Driftwood, Indian almond leaves, peat-filtered water — mimics their natural Amazon habitat
- Dim lighting + floating plants: Neons come from shaded jungle streams. Bright light stresses them
- Dark substrate: Enhances their colors and makes them feel secure
🐠 Tank Mates
✅ Good: Other peaceful tetras, Corydoras, Otocinclus, Hatchetfish, Pencilfish, peaceful Rasboras, small Gouramis (Honey, Dwarf under supervision). ❌ NO: Angelfish (will eat adult Neons), Bettas (may attack), large cichlids, any fish with mouth >2 cm.