Neon Dwarf Rainbow
Neon Dwarf Rainbow (Melanotaenia praecox) is arguably the most popular rainbowfish in the hobby — and for excellent reason. Males are a stunning electric blue with vivid red fins, creating one of the most intense and vivid color combinations available in a small freshwater fish. Females are silver-green with yellow fins — different but equally attractive. At just 2.5 inches, this is one of the few rainbowfish suitable for smaller planted aquariums.
Feeding & Care Tip: Hikari Micro Pellets make an excellent daily staple — soak briefly and crush for juveniles to ensure they can eat comfortably. Supplement 2–3× per week with Hikari Frozen or Freeze-Dried Bloodworms or Hikari Frozen or Freeze-Dried Baby Brine Shrimp to maintain the vivid electric blue and red fin coloration. Feed small amounts 2–3 times daily.
Native to the Mamberamo River drainage in West Papua, Indonesia, the Neon Dwarf Rainbow inhabits clear, slightly flowing streams with vegetation. In the aquarium, soft to medium, slightly acidic to neutral water with a planted environment and open swimming space produces the most vivid coloration. A long aquarium allows the schooling behavior to develop fully.
Keep in groups of at least eight, preferably ten or more. As with most schooling fish, larger groups produce noticeably richer coloration — males in a large group display almost constantly, keeping the electric blue at maximum intensity. Completely peaceful with all non-predatory species. One of the best choices for a planted community aquarium.
One of the most captivating behaviors of rainbowfish is the male display flash — in good light, males develop a brilliant iridescent stripe along the dorsal ridge that they can switch on and off almost instantaneously when competing for female attention. A tank with multiple males and adequate females produces near-constant display behavior, making this one of the most dynamic and entertaining fish in the planted aquarium hobby.
Care & Ideal Parameters
| Difficulty | Easy |
| Temperament | Peaceful — Community |
| Typical Adult Size | 2.5 inches (6.3 cm) |
| Min. Group Size | 8 minimum — groups of 10+ for best male display color |
| Ideal Temp | 73–82°F (23–28°C) |
| Ideal pH | 6.0–7.5 |
| Ideal GH | 5–12 dGH |
| Ideal KH | 2–8 dKH |
| Staple Food | Hikari Micro Pellets |
| Treat / Supplement | Hikari Frozen or Freeze-Dried Bloodworms, Hikari Frozen or Freeze-Dried Baby Brine Shrimp |
| Origin | Mamberamo River drainage, West Papua, Indonesia |
| Notes | Most popular rainbowfish — electric blue body with vivid red fins in males. One of the few rainbowfish suitable for smaller tanks. Soak and crush pellets for juveniles. Groups of 8+ essential for best color. |