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Care Guide for Dwarf Neon Rainbowfish — Housing, Food, and Breeding

The neon dwarf rainbowfish is a beautiful, almond-shaped fish with an iridescent blue sheen that flashes under the light. This hardy species is quite active and has a mild disposition that pairs well with many peaceful and semi-aggressive tank mates. Learn how to care for this beginner-friendly rainbowfish.

What are Neon Dwarf Rainbowfish?

Melanotaenia praecox is a 3-inch (8 cm) rainbowfish found in streams and tributaries of the New Guinea rainforest. The males have a shiny blue body with red-orange fins, whereas the females have a silvery body with yellow fins. As one of the smallest Melanotaenia species, they are relatively inexpensive for a rainbowfish and can be purchased for roughly $5–$7.

dwarf neon rainbowfish


How to Set Up an Aquarium for Neon Rainbowfish

Since they are a fast-swimming fish, we recommend keeping them in a longer aquarium, such as a 20-gallon long or 29-gallon tank at the minimum. Dwarf neon rainbows come from tropical habitats and do well in 74–80°F (23–27°C). While they can handle a wide range of pH and GH, they prefer harder, alkaline water. Since our tap water is relatively soft, we like to use crushed coral to buffer the pH and mineral supplements (e.g., Wonder Shell and Seachem Equilibrium) to increase the GH.

Neon rainbows look amazing in planted aquariums, and taller plants can help block line of sight when the males are tussling with each other. Just make sure the foliage doesn’t get too overgrown because rainbowfish like to have open areas to freely swim.

How many praecox rainbows should be kept together? In general, rainbowfish are schooling fish that require at least 6 or more of the same species. While males are more brightly colorful than females, make sure to keep at least 1–2 females for every male to minimize their squabbling. Plus, males display their best colors and get a shiny stripe on their heads when they show off in front of females.

What fish can live with dwarf rainbowfish? With their deeper-bodied profile and quick speed, they can go well with many similar-sized tank mates, ranging from peaceful to semi-aggressive temperaments. We have kept them with angelfish, pearl gouramis, tetras, corydoras catfish, and smaller cichlids. While they will make a meal out of your cherry shrimp, they seem to leave larger amano shrimp and filter shrimp alone.

dwarf neon rainbowfish in community tank


What do Praecox Rainbowfish Eat?

These omnivorous fish are very easy to feed and will eagerly devour anything you drop in the tank. We like to give them smaller foods that float or slowly sink — such as frozen cyclops, brine shrimp, and nano pellets. They also enjoy bloodworms, flakes, and live fish foods. The key is to provide a variety of foods to ensure they receive a well-rounded diet with all the necessary nutrients.

How to Breed Dwarf Neon Rainbowfish

Rainbowfish are egg scatterers that do not show any kind of parental care. As long as you have fish of both sexes and feed them well, they can easily spawn every day, but their 1 mm eggs produce very tiny fry that can be hard to raise. We like to place a floating spawning mop in the tank to allow the adults to lay their eggs in the yarn strands. After a few days, fill a catch cup with water from the breeding tank and hang it on the inside of the tank in order to keep the water warm. Place the spawning mop full of eggs inside the catch cup and add an air stone to keep the water well-oxygenated. To prevent fungal growth, some breeders add a couple of drops of methylene blue or even a few cherry shrimp to help clean the eggs.

The eggs should hatch in about a week, and the fry must be fed 3–5 times a day with very miniscule foods — like infusoria, vinegar eels, microworms, and powdered fry food. Frequent water changes are also necessary to keep the water quality high. After two weeks, the rainbowfish fry should be large enough to eat live baby brine shrimp, which is the best food to ensure healthy and fast growth of the babies.

dwarf neon rainbowfish with live aquarium plants


We love the neon dwarf rainbow for its iridescent scales, energetic behavior, and compact size as one of the smallest Melanotaenia rainbowfish. If your local fish store doesn't carry them, check out our list of preferred vendors to buy them online. However, if you’re looking for an even more petite species, read our care guide on the forktail blue-eye rainbowfish.

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