Dwarf Neon Rainbowfish
Melanotaenia praecox
Also sold as Praecox
Synonyms Praecox rainbow · Praecox rainbowfish · Neon rainbowfish
Dwarf Neon Rainbowfish (Melanotaenia praecox) is a peaceful freshwater fish that reaches about 6 cm (2.4 in) and swims in open water in a shoal. It wants 73–82°F (23–28°C) and pH 6.5–7.5, is kept in groups of 6 or more, and needs a tank of at least 80 L (21 gal).
At a glance
| Type | Fish |
|---|---|
| Adult size | 6 cm (2.4 in) |
| Minimum tank | 80 L (21 gal) |
| Group size | 6 or more |
| Temperature | 73–82°F (23–28°C) |
| pH | 6.5–7.5 |
| Temperament | Peaceful |
| GH | 5–15 |
| Lifespan | 3–5 years |
| Eats shrimp | Yes |
Before it goes in
- Dwarf Neon Rainbowfish needs at least 80 L (21 gal). The smallest size in this library that clears that is the 60H Tall.
- Keep 6 or more. Below that it hides, colours down and is far more likely to be picked on.
- It eats shrimp. Cherry Shrimp, Crystal Red Shrimp and Bamboo Shrimp are on the menu.
- It holds at 73–82°F (23–28°C). That shares a window with Betta and Cherry Shrimp.
- It jumps. An open-top tank needs a lid or a low water line.
- A group of 6 takes up roughly 61% of what a 60H Tall will comfortably hold, so plan the rest of the stock around it.
What tank size does it need?
At least 80 L (21 gal). The smallest size here that clears it is the 60H Tall.
How many should I keep?
6 or more. Fewer than that and it spends its time hiding instead of out in the open.
Will it eat shrimp?
Yes. Shrimp are food to it, so pick one or the other.
What water does it want?
73–82°F (23–28°C), pH 6.5–7.5, GH 5–15.
How long does it live?
3–5 years in a tank that suits it. That is how long you are signing up for.
Good tank mates
- Tank mates from this library that share its temperature window, are peaceful and eat neither it nor its young: Goldfish, Bristlenose Pleco, Celestial Pearl Danio, Molly and Otocinclus.
- Plants that hold up with it: Hygrophila corymbosa 'Siamensis', Water Sprite, Anubias nana 'Petite' and Cryptocoryne wendtii.
Often compared with
| Dwarf Neon Rainbowfish | Boesemani Rainbowfish | Turquoise Rainbowfish | |
|---|---|---|---|
| Adult size | 6 cm | 12 cm | 12 cm |
| Min tank | 80 L | 200 L | 108 L |
| Group | 6+ | 6+ | 6+ |
| Temperature | 73–82°F (23–28°C) | 75–82°F (24–28°C) | 68–77°F (20–25°C) |
| Eats shrimp | Yes | Yes | Yes |
More livestock
Sources (3) · checked Sep 2026
- What it eats, Mature tankaquariumcoop.com
- aquariumstoredepot.com
- fishlaboratory.com