Product Details

Kali Tawa Rainbowfish – Melanotaenia sp. “Kali Tawa”

Overview:

The Kali Tawa Rainbowfish is a rare and highly sought-after undescribed rainbowfish from West Papua, admired for its shimmering blue-green body, pale contrasting fins and vivid red tail in mature males. Although sometimes described as a dwarf rainbowfish, Melanotaenia sp. “Kali Tawa” is still an active shoaling fish that needs clean, well-oxygenated water and room to move. Large specimens can already show excellent colour, especially in a settled mixed-sex group with a good diet and stable conditions.

Key Identification:

Common Name: Kali Tawa Rainbowfish
Other Names: Kali Tawa Dwarf Rainbowfish, Tawa Rainbowfish, Lengguru Rainbowfish, Red-tailed Kali Tawa Rainbowfish
Scientific Name: Melanotaenia sp. “Kali Tawa”
Fish Type: Rainbowfish
Water Type: Freshwater

Natural Range & Habitat:

The Kali Tawa Rainbowfish is an undescribed species from the Lengguru Valley / Lengguru Mountains region of West Papua, Indonesia. Aquarium Glaser notes that it entered the aquarium hobby in 2019 and remains scientifically undescribed, while German trade sources describe it from the remote Lengguru Valley in south-western New Guinea.

Its habitat is associated with clear, flowing streams in limestone karst country. This means aquarium care should focus on clean water, good oxygenation, moderate flow and stable mineral content rather than soft acidic blackwater conditions. Collection and trade notes also describe fish staying near bankside debris, roots and shelter.

Appearance & Adult Size:

Mature males are especially attractive, with a metallic blue to blue-green upper body, paler lower body and a bright red tail. Some lines also show orange to red highlights along the fins and flanks, depending on sex, age, mood and lighting. Females are usually more subtle but are important for natural group behaviour and male display.

This is a smaller Melanotaenia, usually reaching around 6–8 cm. Some trade references give 6–7 cm, while other locality notes describe adults reaching about 8 cm.

Aquarium Suitability:

This species is best suited to a mature planted aquarium, specialist rainbowfish setup or peaceful community with similar-sized active fish. It appreciates open swimming room through the middle of the aquarium, with plants, wood, roots or décor around the edges for cover. Large sale-size fish should be given space immediately, as adult males are active and display frequently.

It is not suitable for nano aquariums, very soft acidic setups, aggressive communities or slow timid fish that may be stressed by fast feeding behaviour.

Recommended Aquarium Size:

A practical minimum is 120 litres for a group, with 150 litres or more preferred for a larger shoal and better display behaviour. A tank length of at least 90 cm is recommended, as this is an active midwater fish despite its moderate adult size.

Water Conditions:

Temperature: 23–27°C
pH: 7.0–8.0
Hardness: Moderately hard to hard preferred
Additional Notes: Provide clean, well-filtered and well-oxygenated water with regular partial water changes. The Lengguru karst habitat suggests mineral-rich water, and trade guidance describes the natural water as relatively hard and calcareous. Avoid consistently high temperatures if breeding is intended, as hobby breeding notes suggest cooler mid-20s °C conditions may help achieve a more balanced sex ratio.

Temperament & Tank Mates:

Aquarium Category: Community Fish

Kali Tawa Rainbowfish are peaceful, active shoaling fish. Suitable tank mates include small to medium rainbowfish, danios, peaceful barbs, robust rasboras, larger small tetras, Cory-type catfish suited to similar water, bristlenose plecs and other calm community fish that enjoy clean, oxygenated water.

Avoid aggressive cichlids, persistent fin-nippers, very tiny fish and slow delicate species that may be intimidated at feeding time. Keep in a group of at least 6, with 8–10 or more preferred. A mixed-sex group gives the best colour and display, as males intensify when showing to females and rival males.

Feeding:

Kali Tawa Rainbowfish are easy-feeding omnivores once settled. Offer quality flakes, small granules and rainbowfish pellets as the staple diet. Supplement with frozen or live foods such as daphnia, brineshrimp, cyclops, mosquito larvae and small bloodworm. Include vegetable or algae-based foods for balance. They are quick feeders, so use measured portions and make sure quieter tank mates still get food.

Behaviour in the Aquarium:

This is an active midwater to upper-level rainbowfish that swims in a loose group. Males display with raised fins, brighter body colour and a vivid red tail, especially in the morning, after water changes or when females are nearby. They are lively rather than aggressive, and large settled males can become very eye-catching in a planted display.

Care Notes:

Keep in a mature aquarium with stable water, good oxygenation and a secure lid, as rainbowfish can jump when startled. Do not keep singly or in pairs, as small numbers can become nervous and less colourful. Locality fish such as Kali Tawa should not be mixed with other similar Melanotaenia if breeding may occur, as this can lose the identity of this rare strain. Maintain clean water and avoid overcrowding, as colour and health are closely linked to water quality.

Recommended For:

Beginner to intermediate

Availability:

Rare / Specialist rainbowfish strain / Captive-bred when available

Image Disclaimer:

All images are a visual representation of the fish you will receive, made to be as accurate as possible. Natural variation in size, colour, pattern and markings can occur between individual fish.