Yellow Rainbow
Yellow Rainbow (Melanotaenia herbertaxelrodi) is a vivid, medium-sized rainbowfish with a warm golden-yellow to lemon body and iridescent blue-green highlights along the flanks. The yellow coloration is unusually bright and uniform for a Melanotaenia — creating a fish that catches the eye immediately in a planted aquarium.
Feeding & Care Tip: Sera Vipan Tropical Flakes and Hikari Micro Pellets make excellent daily staples. Supplement 2–3× per week with Hikari Frozen or Freeze-Dried Bloodworms to enhance the vivid yellow coloration. Crush flakes for juveniles; soak pellets.
Native to Lake Tebera and the Purari River system in the Southern Highlands of Papua New Guinea. This species inhabits the margins of lakes and slow-moving streams. It adapts well to a range of aquarium conditions and is one of the more undemanding of the Papuan rainbowfish.
Keep in groups of at least six with mixed sexes. Males display actively with color intensification and fin-spreading. The yellow coloration is most vivid when males are competing. Completely peaceful with other medium to large community fish.
A well-planted aquarium with open swimming space in the center replicates the rainbowfish's natural riverine habitat. These are active, fast-swimming fish that appreciate length more than height — a longer tank allows them to build up speed and display properly. Good filtration and regular partial water changes are important, as rainbowfish are sensitive to deteriorating water quality. Avoid very small or slow-moving tankmates that may be outcompeted at feeding time.
Care & Ideal Parameters
| Difficulty | Easy |
| Temperament | Peaceful — Community |
| Typical Adult Size | 4.0 inches (10 cm) |
| Min. Group Size | 6 minimum — mixed sexes for best male coloration |
| Ideal Temp | 72–82°F (22–28°C) |
| Ideal pH | 7.0–8.0 |
| Ideal GH | 8–20 dGH |
| Ideal KH | 4–10 dKH |
| Staple Food | Sera Vipan Tropical Flakes; Hikari Micro Pellets |
| Treat / Supplement | Hikari Frozen or Freeze-Dried Bloodworms |
| Origin | Lake Tebera and Purari River, Southern Highlands, Papua New Guinea |
| Notes | Named for Herbert Axelrod, prominent aquarium fish author and collector. Warm golden-yellow coloration is unusually vivid for Melanotaenia. Hardy and adaptable. |
