Forktailed Rainbowfish (Pseudomugil Furcatus)


Pseudomugil Furcatus is prevalent in eastern Papua New Guinea in Kwagira River and Peria Creek. The streams in the rainforests of Dyke Ackland to Collingwood bays are housing it. Researches are extended to find if the species is also existing in other closer zones.

This fish is quite popular in the aquarium hobby. But only the type which is commercially bred from a single collection obtained from Papua New Guinea in 1981 is traded in the hobby. Wild species are not suitable for aquarium hobby.



Forktailed Rainbowfish rarely reaches the size of 7 cm. It is peaceful while living in a community of its kind. It can also live in a community tank with other aquarium fish of small size that is not behaving violently.

When this fish is transferred to a new aquarium, it adapts to the new environment gradually. They can adapt to different water conditions ranging from acidic to alkaline and hard to soft water conditions.

Pseudomugil Furcatus stays active and playful in the aquariums. It is agile and swims around, in and out of the vegetation in the tank happily all day long. For keeping their life active and well-maintained, make a combination of males and females in the tank. For every 2 females, keep 1 male in the tank for the best. It is best to keep these fish in larger numbers since they feel safe in larger schools and display the best colors. So, get a number as large as your tank can accommodate and you can afford for the best view and healthy community.


This fish is impressively colored and is one of the gorgeous fish among the aquarium fish. It has bright blue eyes and gray-green body color, and all the fins are with bright yellow edges. A black margin exists on its tail, dorsal and rear fins.

The juvenile fish has faint colors but the adult fish is bright and intensely colored. The coloration becomes better with a high-quality omnivorous feeding diet. This fish reaches the best coloration when kept in schools of six or more fish with males and females combined.


It looks like to its close relative Popondetta Rainbowfish. The Forktail Blue-eye is uniform in color and design. While swimming close to the surface, the fish keeps its pectoral fins raised to the surface.

Water Parameters

Temperature: 24-28°C
pH: 6,5 – 8,0
Hardness: 5-15 dGH


Feeding is not a serious problem with Forktail Rainbowfish. They are omnivorous and live a healthy life on a combination of frozen, dried, and fresh foods. Live food is also significant for them, especially for the male in the mating season. Forktail Rainbowfish also eats zooplankton and phytoplankton and these are its preferred foods in the natural environment. But in an aquarium, they can easily adapt to eat flakes of good quality. Still, it is better to feed them with microworms, brine shrimp, Daphnia, Moina, etc.

Tank Maintenance

Forktail Rainbowfish is naturally accustomed to clear waters with thick vegetation in Papua New Guinea rivers and streams. This fish is an excellent choice for a small or medium-size aquarium that is well-planted. It is a peaceful fish and it is easy for it to get along with other petite and peaceful fellows in the tank.

The choice of other fish can be catfish or goby and many diminutive cyprinids. Small gobies dwell in the bottom while Forktail Rainbowfish occupy the middle and upper water levels.

It can also be kept as a single species in the form of a shoal. To make a completely good environment for this fish, choose some floating plants like hornwort and duckweed; they are very good for this schooling fish to provide secure feeling zones. Add tangles of wood to the tank. Spindly Sumatra wood is ideal for this purpose. The thick vegetation and tangles of wood diffuse the light. If you like to raise fry with the adults in the same tank, add some aquatic moss with fine leaves. The best choice is Taxiphylum sp. for breeding purposes.

Keep the tank well-oxygenated and the water properly filtered. But make sure that no sharp change in the water chemistry or temperature happens. A group of 10 or more fish is the ideal number to keep in a tank around 40 liters. The display of their body colors and designs also looks more striking while keeping them in the optimum numbers with a group consisting of both males and females..

Forktail Rainbowfish lives in the upper and medium level of the water and is used to jumping sometimes. To keep them from jumping out of the water and die, keep the water low or cover the aquarium with proper cover.


For the breeding tank of Pseudomugil furcatus, plenty of Java Moss and floating plants that have long trailing roots or spawning mops must be added to the tank. The temperature should be set towards the higher range of 1-2°C. The aquarium also can be placed in a location where it can receive some natural sunlight in the morning. The morning sunshine induces this fish into the spawning state.

Intense courtship takes place and the male spreads its fins and chases the females and can be persistent in that. Sometimes he becomes aggressive towards the female which can cause non-serious hurts to the female. If the aggression is at a very high level separate the male from the female because females are not compatible with the males and try spawning at a later time.

After successful mating, the female scatters the eggs over the plants or mop. The eggs depositing procedure continues for several days or weeks. The eggs need to be instantly removed from the breeding tank because the parent fish might consume them. The eggs take two to three weeks in incubation. The time of hatching dependent on the temperature.

Following hatching, the fry starts free swimming and feeding at once. The fry doesn’t receive any parental care. In the first week of their life, the fry eats infusoria and finely powdered fry food. The feeding regime must be adjusted to feed in small amounts but several times a day. When the fry grows bigger, they can start eating micro worms and brine shrimp.

The tank water needs to be changed partially and slowly so that no sharp change in the water chemistry happens. The fry is highly sensitive to sharp changes in the environment and it can be fatal. The fry becomes mature at the age of 3 to 4 months. Also, make sure that the tank has plenty of floating plants because the fry loves hiding places.

Image Source: Plantedtankaqua

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