Yellow Rainbowfish: A Comprehensive Guide

Yellow Rainbowfish (Melanotaenia herbertaxelrodi) is a stunning freshwater fish known for its vibrant yellow coloration and peaceful nature. This guide provides detailed information on Yellow Rainbowfish, covering their natural distribution and habitat, dietary needs, tank mates, and spawning practices.

Distribution and Habitat

Yellow Rainbowfish is native to Papua New Guinea, specifically the streams and rivers of the Markham River basin. They inhabit clear, slow-moving waters with dense vegetation and sandy or rocky substrates. These environments are characterized by moderate temperatures and high water quality.

Size and Appearance

Yellow Rainbowfish typically grows to a size of about 3-4 inches (7.5-10 cm). They have a slender, elongated body with a brilliant yellow coloration and sometimes exhibit blue or greenish hues along their flanks. Their fins are often edged in red or orange, adding to their striking appearance.

Water Parameters

Maintaining optimal water conditions is crucial for the health of Yellow Rainbowfish:

  • Temperature: 68-82°F (20-28°C)
  • pH: 6.5-8.0
  • Hardness: 8-25 dGH

These fish thrive in well-maintained aquariums with stable water conditions and good filtration to mimic their natural habitat.

Tank Mates

Yellow Rainbowfish are peaceful and social fish, making them ideal for community tanks. Suitable tank mates include:

  • Tetras
  • Rasboras
  • Corydoras
  • Apistogramma
  • Other rainbowfish
  • Livebearers like guppies and platies

Avoid housing them with larger or aggressive fish that might intimidate or harm them.


In the wild, Yellow Rainbowfish are omnivores, feeding on small invertebrates, plant matter, and detritus. In captivity, they thrive on a varied diet:

  • High-quality flakes or pellets formulated for omnivores
  • Live or frozen foods such as bloodworms, brine shrimp, and daphnia
  • Blanched vegetables like spinach and zucchini

A varied diet ensures their vibrant coloration and overall health.


Yellow Rainbowfish are active and engaging fish, often seen swimming in the mid to upper levels of the tank. They are social creatures that should be kept in groups of at least six to promote natural behaviors and reduce stress. Their peaceful nature makes them excellent tank mates for a variety of species.


Breeding Yellow Rainbowfish in captivity can be achieved with the right conditions. Key points include:

  1. Conditioning: Feed the breeding group a high-protein diet, including live and frozen foods, for several weeks.
  2. Breeding Tank: Set up a separate breeding tank with fine-leaved plants or spawning mops to provide surfaces for egg deposition.
  3. Spawning Process: Perform regular water changes with slightly cooler water to stimulate spawning. Females will scatter adhesive eggs on plants or mops. Remove the adults after spawning to prevent them from eating the eggs.
  4. Hatching: Eggs typically hatch within 7-10 days. Feed the fry infusoria or liquid fry food until they are large enough to consume baby brine shrimp.

Fun Facts

  • Yellow Rainbowfish are known for their vibrant yellow coloration, making them a favorite among aquarists.
  • They are active swimmers and thrive in well-planted aquariums with plenty of open swimming space.
  • These fish are social and prefer to be kept in groups, which enhances their natural behaviors and overall well-being.


Yellow Rainbowfish, with their brilliant colors and active demeanor, make a delightful addition to any freshwater aquarium. By understanding their natural habitat, dietary needs, and care requirements, aquarists can ensure these charming fish thrive in captivity. Whether you're a novice or an experienced fish keeper, Yellow Rainbowfish offers a glimpse into the world of dynamic and interactive freshwater fish.

Looking to add Yellow Rainbowfish to your aquarium? We recommend purchasing from trusted suppliers like The Wet Spot Tropical Fish and Dan's Fish for high-quality, healthy fish. These reputable retailers offer a great selection and expert advice to ensure you find the perfect fish for your tank.