Not furry, but we like them anyway.
Forktail Blue-eye
Pseudomugil furcatus Nichols, 1955
Also called Forktail rainbowfish, Yellow forktail
From Eastern Papua New Guinea: lowland rainforest streams of the Musa and Kwagila river basins (Northern and Milne Bay provinces), between Dyke Ackland Bay and Collingwood Bay.123
At a glance the quick version
FishBase: 5 cm SL males, 4 cm SL females; Seriously Fish gives 6 cm SL
Looks how to spot one
Scaled, slender blue-eye
A small, slim fish with a deeply forked tail, which gives it its name. Males are more patterned and colourful than females and have longer dorsal and anal fins.1
Personality what they are like
Peaceful and sociable; it suits a community of similar-sized calm fish such as small gobies and gudgeons.12
Daily activity how busy a day looks
An active shoaling fish that swims in the upper and middle water, in gentle to moderate flow.1
Grooming and care the hands-on bits
Needs a biologically mature tank with stable water conditions; Seriously Fish rates it moderate to keep.1
Home where they are happiest
Minimum tank base about 60 x 30 cm (around 54 litres). Temperature 24-28 °C, pH 7.0-8.0, hard water (Seriously Fish gives 15-30 dGH; FishBase lists 5-12 dH). Dense plants, driftwood, floating plants and well-oxygenated water.12
Food basics what goes in the bowl
In the wild it eats tiny floating plankton and invertebrates. Offer small live foods such as Daphnia, Moina, baby brine shrimp and microworms, plus small floating dry food.1
Company who they like around
Keep a group of at least 8-10.1
The story where it all began
Nichols described it in 1955. It spent some years in the genera Popondetta and Popondichthys before being returned to Pseudomugil in 1989. The fish in the hobby are believed to descend from a single collection made in 1981.13
Fun facts for the dinner table
- 1
The species name furcatus means 'forked', after its tail.1
- 2
Pseudomugil means 'false Mugil', a nod to the grey mullet genus.1
- 3
A male may spawn with several females in one day, and spawning can go on all day in warm weather.1
- 4
Its eggs take around three weeks to hatch, which is long for such a small fish.1
Recognised by the official bits
- IUCN Red List
- Data Deficient (assessed June 2020)2
- Taxonomy
- Family Pseudomugilidae; described by Nichols in 1955; formerly placed in Popondetta and Popondichthys1
The care rhythm a typical week and year
A typical home-care rhythm for a Forktail Blue-eye. A starting point, not a vet's advice.
- FeedingSmall amounts once or twice a dayevery day
- Temperature checkevery day
- Water changeAbout 25% of the waterevery week
- Water testevery week
- Glass cleanevery week
- Filter rinseRinse in old tank water, never tap waterevery month
Owner questions the things everyone asks
How often should I feed my Forktail Blue-eye?
Feed small amounts once or twice a day. Furry Diary's starting plan is to feed daily, offering only what they can eat in a couple of minutes.1 Pet Wiki plan
What does a Forktail Blue-eye eat, and what should it never eat?
They enjoy small live foods like Daphnia, baby brine shrimp, and microworms, plus tiny floating dry food. Never feed large or sinking foods that could cause digestive issues; ask your vet or a good breeder for a safe list.1
How much space does a Forktail Blue-eye need?
A minimum tank base of about 60 x 30 cm (around 54 litres) is recommended for a small group. They are active shoalers, so more space is always better.1
What temperature, light or water does a Forktail Blue-eye need?
Keep water temperature between 24-28 °C, with a pH of 7.0-8.0 and hard water (15-30 dGH). Provide dense plants, driftwood, floating plants, and well-oxygenated water with gentle to moderate flow.12
How often should I clean a Forktail Blue-eye's home?
Furry Diary's plan suggests a weekly 25% water change and glass cleaning, plus a monthly filter rinse in old tank water (never tap water). Always test water weekly to keep conditions stable. Pet Wiki plan
Can a Forktail Blue-eye live with others?
Yes, they are peaceful and sociable, ideal for a community of similar-sized calm fish like small gobies and gudgeons. Keep a group of at least 8-10 of their own kind for best wellbeing.12
How long does a Forktail Blue-eye live?
Lifespan varies depending on care and environment; ask your vet or a good breeder for typical expectations. With stable water and good diet, they can thrive for a few years.
Can I handle a Forktail Blue-eye?
No, handling is not recommended as it stresses the fish and can damage their delicate scales and fins. Enjoy watching them swim in their tank instead.1
Written from the sources on this page, a few checked guides (VCA, ASPCA, RSPCA) and Pet Wiki's own starting care plan. A friendly guide, not a vet's advice.
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Where this comes from
Every fact on this page has a numbered source. Spotted an error? support@petwiki.app.
- Seriously Fish: Pseudomugil furcatus (Forktail Blue-eye) seriouslyfish.comused for names, distribution, habitat, tank size, water parameters, diet, behaviour, group size, history, fun facts
- FishBase: Pseudomugil furcatus, Forktail rainbowfish fishbase.seused for length by sex, distribution, water ranges, IUCN status
- Wikipedia: Pseudomugil furcatus en.wikipedia.orgused for distribution, taxonomy history
Checked 2026-09-30. Text is written in our own words from these sources.