叉沼汉鱼 · Forktail Blue-eye

Overview

Pseudomugil furcatus suits a densely planted aquarium and is more secure in a group of at least eight to ten. Stable, relatively hard water near neutral to alkaline is important. Breeders should also account for possible inbreeding and low egg fertility in captive lines.

Distribution & habitat

It is endemic to a small part of eastern Papua New Guinea's Northern and Milne Bay provinces, including the Musa and Kwagila drainages. Lowland forest streams are typically clear, heavily vegetated, and slow to moderately flowing.

Monsoon rains raise water volume and turbidity, while dry periods may leave isolated pools. These natural changes do not imply a need to recreate unstable conditions in captivity.

Aquarium setup

Use a base around 60 × 30 cm, combining dense plants with swimming room. Floating cover and wood can soften the light. Fine moss and elevated shelter are useful when attempting to retain offspring with adults.

Maintain oxygen-rich water and moderate circulation in an established system. Avoid immature aquariums and rapid chemical changes. Keep temperature within its established maintenance range rather than treating it like a cool-tolerant relative.

Diet & feeding

Floating and suspended plankton and small invertebrates form its natural food base. Water fleas, brine-shrimp nauplii, and microworms are appropriate live options. Small or crushed floating dry food is also taken when particles fit the mouth.

Behaviour & compatibility

Peaceful companions of comparable size and matching needs can be selected. At least eight to ten conspecifics reduce nervousness and encourage male displays.

Sexual dimorphism

Males develop stronger color and pattern, with noticeably elongated unpaired fins at maturity.

Breeding

It scatters eggs without care and may eat eggs or fry. Warm conditions favor daytime spawning, with small batches attached to plants or other surfaces over several days. A male may spawn with multiple females.

One approach isolates six to eight adults, or a male and two or three females, with sponge filtration and mops or moss. Collect eggs daily for separate incubation. Alternatively, a mature planted colony aquarium can retain a smaller number of young. Moss placed high in the water and trailing floating roots shelter the surface-oriented fry.

Hatching takes roughly twenty-one days. Fry immediately accept brine-shrimp nauplii, microworms, or appropriately sized powdered food. Offer small meals at least twice daily, removing leftovers and making regular small water changes.

Captive lines have reportedly derived largely from an early single collection, raising concerns about reduced fertility, deformity, and shortened lifespan. Eggs from females younger than roughly eight months often fail to develop, while even mature breeders may produce more than half infertile eggs. Egg production alone therefore does not guarantee reliable fry output.

Notes

The species has undergone several generic-name changes. Older labels need not denote different species. Commercial abundance does not remove the importance of breeding-line history and reproductive quality.