Green neon tetra

Overview

The green neon tetra (Paracheirodon simulans) is the smaller, warmer-water cousin of the common neon tetra. At barely 3 cm it packs a shimmering blue-green stripe that lights up a shaded, planted tank, and a big shoal drifting through dark water is one of the finest sights in the hobby. It is peaceful, hardy once settled, and ideal for a nano or blackwater-themed aquarium.

Tank & water

A shoal needs a minimum of 40 litres (10 gallons), though a longer tank shows them off better. Priorities:

• Warmth: these fish come from very warm Amazon waters — hold 24–29 °C with a reliable heater.
• Soft, acidic water: they thrive at pH 4.0–6.5 and low hardness. Botanicals and driftwood that tint the water suit them perfectly.
• Gentle filtration: a filter with soft flow keeps water clean without buffeting such small fish.
• Planting and shade: dense plants and dim lighting bring out their colour and confidence.

Feeding

Green neon tetras are micro-omnivores with tiny mouths. Feed a quality micro-pellet or crushed flake as a staple, plus small frozen or live foods such as baby brine shrimp, daphnia and cyclops. Feed small amounts once or twice a day, only what they clear in a minute or two. Varied small foods keep their colour rich and support conditioning.

Tankmates

These are gentle shoalers best kept with other calm nano species. Good companions include ember tetras, chili rasboras, pygmy corydoras, otocinclus and dwarf shrimp. Avoid anything large, boisterous or fin-nipping. Keep them in a group of at least eight — see good tankmates for neon tetras for more pairing ideas.

Common mistakes to avoid

• Keeping them in hard, alkaline water (they need soft and acidic)
• Too small a group, which causes stress and faded colour
• Adding them to an immature tank
• Housing them with big or nippy fish

Set up a warm, soft, planted tank — our best nano aquarium picks are a good start — and a shoal of green neons becomes a living jewel.