Lake Furnusu Rainbow
Lake Furnusu Rainbow (Melanotaenia mairasi) is an attractive species from West Papua named for Lake Furnusu — a small, remote lake in the Bird's Head Peninsula region. Males display a warm orange-red body with iridescent blue-green highlights. Listed as Vulnerable on the IUCN Red List, captive-bred aquarium populations are important for this species.
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. Crush flakes for juveniles; soak pellets.
Native to Lake Furnusu and surrounding waters in the Bird's Head Peninsula, West Papua, Indonesia. Inhabits slow-moving to still waters. Slightly hard, neutral to alkaline water suits this species well. Note: the Shopify SKU contains a typo (Melanotaneia) — the correct spelling is Melanotaenia mairasi.
Keep in groups of at least six with mixed sexes. Completely peaceful with other medium to large community fish. IUCN Vulnerable — aquarium breeding contributes meaningfully to conservation.
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 | 8–18 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 Furnusu, Bird's Head Peninsula, West Papua, Indonesia |
| Notes | IUCN Vulnerable — aquarium populations important. Named for Lake Furnusu. Warm orange-red male coloration. Note: scientific name sometimes misspelled as Melanotaneia — correct spelling is Melanotaenia mairasi. |
