Dwarf neon rainbowfish

Overview

The dwarf neon rainbowfish (Melanotaenia praecox) is the compact version of the big rainbows: just 2-2.4 in (5-6 cm), with a metallic blue body that flashes like neon as it turns, plus red fins in males and yellow-orange fins in females. It comes from the Mamberamo River basin in western New Guinea (Indonesia), where it lives in clear, well-vegetated streams.

It's one of the best rainbowfish for a mid-size planted community tank: peaceful, active without being frantic, hardy and easy to feed. A group swimming in the open in front of green plants is a real showpiece. It's a great next step for hobbyists moving up from small tetras.

Care and tank setup

It's small, but it swims a lot and in groups, so plan on about 30 gallons (120 L) and a 30-36 in (80-90 cm) tank at minimum. Mix densely planted areas with an open swimming lane. It tolerates a fairly wide range of water, from slightly acidic to slightly alkaline, as long as it's stable and clean.

• Keep 6 or more; with several males you'll see their color displays.
• Gentle to moderate flow and weekly water changes: color fades when nitrates run high.
• Use a tight lid, as rainbows jump.

Good tank mates include medium tetras, rasboras, corydoras, honey gouramis, loaches and small plecos. It leaves adult shrimp alone, though it will eat the odd shrimplet. Avoid large or aggressive fish that bully it. A common mistake is buying juveniles for a small tank; they grow and need swimming room.

Feeding

An omnivore that takes almost anything. Feed a quality flake or micro-pellet as the staple and offer small live or frozen foods a few times a week: brine shrimp, daphnia, cyclops or bloodworms. It likes to eat at the surface and in midwater. Offer small portions once or twice a day that are gone within a couple of minutes.

Breeding

It's relatively easy to breed. Like other rainbows, it spawns daily for weeks, scattering a few sticky eggs into fine plants, moss or a yarn mop. The parents don't care for the eggs and will eat them, so move the mop or eggs to a separate container filled with tank water. Fry hatch in 7-12 days and start on infusoria or liquid fry food, then baby brine shrimp.

Compatible tank mates

Species from our database that share water parameters, size and temperament with the Dwarf neon rainbowfish. Calculated from the data in each profile.

Check the compatibility of your whole tank →

What not to keep it with

Popular species you shouldn’t house with the Dwarf neon rainbowfish, and why.

• Clown loach: one may eat the other due to size
• Oscar: one may eat the other due to size, incompatible temperaments

Recommended equipment

What you need to keep the Dwarf neon rainbowfish healthy, checked against Amazon stock.