Forktail Blue-eyes (Pseudomugil furcatus) are one of those fish that immediately catch your eye – small, colorful, and full of energy.
In this article, I’ll walk you through what they eat, how to breed them, and how to make them feel right at home in your tank.
If you’re into fish that look amazing and have personality too – stick around.
Origin
The Forktail Blue-eye originates from the southern regions of Papua New Guinea. It is most commonly found in the river basins of the Musa and Kwagila Rivers, which flow into Dyke Ackland Bay and Collingwood Bay, respectively.
There’s a good chance it inhabits other nearby rivers as well, but this has yet to be fully confirmed.
Its natural habitat consists of calm, lowland streams, often surrounded by dense, lush vegetation.
The water must be clean, and the current relatively gentle—though it may pick up speed from time to time.
Papua New Guinea is known for its stable climate, but between December and March, everything changes with the arrival of the northwest monsoon.
Rain can pour almost continuously, and the rivers swell—becoming murky, fast-flowing, and full of surprises.
Size
Adult Forktail Blue-eyes are not large—typically reaching about 5 to 6 cm in length (around 2–2.4 inches).
Males tend to be slimmer and more elongated, while females are slightly smaller with rounder bodies.
The differences are subtle but noticeable, especially when observed closely.
Availability
Good news is that Forktail Blue-eyes are currently quite easy to find in the aquarium trade, thanks to successful captive breeding.
Fun fact: all existing populations stem from a single collection gathered in 1981. This is why some experts are concerned about their genetic diversity.
Wild specimens are no longer sold, which is actually a positive—helping to preserve their natural habitat.
As for specific retailers:
USA:
- Aquarium Fish Depot (San Diego, California): $7.99 each – but availability may vary.
- Discus Madness: larger specimens (1–1¼ inches) for $12.00.
- The Shrimp Farm: offers a 3-pack for $19.99 (approx. $6.66 each).
- TRiN’s Tropical Fish: $9.99 per fish.
It’s worth checking stock and shipping options regularly, as they tend to change quickly.
Europe:
- Garnelaxia (Austria): €7.90 each.
- Garnelio (Germany): €8.99, currently discounted from €9.69.
- AquaTropics (United Kingdom): 10-pack for £29.00 – just under £3 per fish.
Appearance and Sexual Dimorphism
This is a small yet striking fish. Its body is silvery, slightly elongated, with a shimmering bluish sheen. The belly is somewhat yellowish. But the real attention-grabbers are the fins: intensely yellow and black, especially in males.
Females have almost transparent pectoral and pelvic fins, while males’ fins are vivid and eye-catching. Males also have a longer dorsal fin and are overall more flamboyant.
Their most distinctive feature is the forked tail—with yellow-tipped lobes that look a bit like tiny waving pompoms.
Sounds odd? Just see it once, and you’ll understand.
As is typical for rainbowfish, females are more subdued in coloration, but it’s best to keep them with males—ideally two females per male.
Why? Because that’s when males truly shine—literally and figuratively.
They swim around each other in circular, display-like dances, showcasing their colors in a mesmerizing performance. It’s a spectacle worth watching.
Behavior
These are lively, energetic fish that bring both color and movement to the aquarium. They’re peaceful, but they can’t stand being alone — they thrive best in larger groups.
A minimum of 8–10 individuals is needed for them to feel safe and behave naturally. Otherwise, they may become stressed and hide in the corners.
Males are especially active. They love to show off their fins and will sometimes even “compete” for the attention of females — all within the bounds of fishy decency, with no harm done. It’s like a little underwater show that makes the aquarium come alive.
They usually swim in the middle and upper levels of the tank, which makes them compatible with species that stick closer to the bottom.
Their constant movement ensures the top of the tank never feels empty or dull.
What about breeding? During spawning, males display themselves even more, while females lay eggs among fine-leaved plants or on special spawning mops.
Spawning lasts several days, and depending on the temperature, fry appear within 7 to 14 days.
Care
Forktails primarily need clean, well-oxygenated water. Regular water changes are essential — there’s no getting around it.
They thrive in a well-planted tank that offers both hiding places and open areas for swimming.
When they have both shelter and space, their colors truly shine — they can look absolutely stunning.
They are schooling fish — solitary life is not for them. To keep them comfortable, it’s best to keep them in groups of at least 8–10. They coexist peacefully with other small, calm fish — especially those with similar care requirements.
They’re also somewhat delicate. If you need to move them, always use a soft net — no sharp edges!
Some aquarists go a step further and use special glass tubes, like those used for collecting fry — yes, it’s that precise. With proper care, they can live up to 3 years, though some report lifespans of only 1–2 years. Sometimes this is due to inbreeding, sometimes to suboptimal tank conditions.
Tank Requirements
The tank should be well-covered — not only to prevent jumping but also to reduce evaporation.
Lighting? Preferably on the stronger side, so the plants can thrive. A filter and an air pump are essential. It also helps if the water has a gentle current, like in a forest stream — the fish really appreciate that.
The bottom should be covered with about 5 cm of well-rinsed sand. Add some roots, driftwood, lignite, or even halved coconut shells — this creates a more natural environment.
Plants should be placed along the sides and back of the tank, leaving the center open for swimming.
Floating plants with feathery roots, like pistia, salvinia, or limnobium, are great additions — they look beautiful and give the fish a sense of security.
One crucial point: the water must be clean, with no traces of ammonia or nitrite. Even nitrate levels should stay below 20 mg/l. To maintain this, weekly water changes of about 25% and high-quality filtration are a must.
Minimum tank size? 60 × 30 cm — smaller setups just won’t do. Temperature should remain steady between 24–28 °C, as these fish dislike large fluctuations. pH should ideally be between 7.0 and 8.0.
Diseases
In general, these fish are fairly hardy, but like any living creature, they can fall ill if the water quality is poor or if they’re stressed. The most common issues include:
- Ichthyophthirius (commonly known as “Ich” or fish white spot disease)
- Fin rot
- Fungal infections
The best prevention? Maintain high water quality, perform regular water changes, and always quarantine new fish before introducing them to the main tank.
Tank mates
Forktails are quite gentle and get along well with other peaceful species of similar size — such as rasboras, tetras, or corydoras.
One thing to keep an eye on is their appetite — they’re quick and agile, and may dominate the group during feeding. It’s worth checking to ensure all fish get their share.
With shrimp? They’re usually fine with adult dwarf shrimp, but if something small flashes in front of their nose… well, it might disappear. It’s best not to risk it with juveniles.
Diet
In the wild, they feed primarily on microscopic organisms – plankton, small invertebrates, and whatever is suspended in the water column.
In an aquarium, they’re relatively easy to care for, though it’s important to offer appropriately sized food.
They readily accept frozen foods (such as cyclops, moina, brine shrimp, and daphnia) and high-quality dry food. And if you really want to spoil them – try offering live fruit flies. Now that’s a feast!
Breeding
For spawning, a small tank with a sandy bottom, a clump of moss, and a few floating plants – ideally Riccia fluitans – will do the trick.
Gentle bubbles from an air stone are a nice bonus. Placing the tank near an east-facing window is also helpful – morning light works wonders.
Introduce one male and 2–3 females, or a whole group with the right male-to-female ratio. Spawning usually occurs at dawn.
Over several days, the fish lay eggs, most often in the moss. You can move the moss clumps to a separate tank, although some aquarists leave them in the main tank – the parents rarely eat the eggs, but the fry… that’s another story.
So it’s best to remove the adults after about two weeks, before the larvae appear.
The fry hatch in 15–20 days. Once they begin to swim, feed them infusoria, followed a week later by freshly hatched brine shrimp.
In Conclusion
Pseudomugil furcatus, commonly known as the Forktail Blue-eye, are stunning, lively fish that truly bring any aquarium to life.
Their small size, vivid coloration, and relatively easy care requirements make them an excellent choice for both beginner and experienced aquarists.
If you provide them with a clean, well-structured environment, they won’t just be a joy to watch – they might even breed and display their full charm.
And really, isn’t that what makes fishkeeping so rewarding?
