黑裙鱼 · Black Widow Tetra

Overview

Gymnocorymbus ternetzi, the black skirt tetra, is an active, adaptable aquarium fish. Young specimens show the strongest black coloration, which naturally softens with age. Keeping a substantial group helps contain disputes and fin nipping within the shoal.

Distribution & habitat

It originates from the Paraguay and Guaporé drainage systems in Brazil, Bolivia, and Argentina. Slow small streams and tributaries with overhanging vegetation are typical habitats. Aquarium supplies predominantly come from captive breeding.

Aquarium setup

Combine open swimming room with quieter sheltered areas. Dense patches of plants and floating cover soften the light and improve the display of color. It tolerates varied layouts, provided vegetation does not occupy all of the group's movement space.

Diet & feeding

This is an omnivore. Flakes or granules form a practical base, with regular small live and frozen foods such as water fleas and bloodworms.

Behaviour & compatibility

It is generally peaceful with suitable livebearers, danionins, rasboras, other tetras, and gentle bottom dwellers. More robust dwarf cichlids can also be compatible. Maintain at least twelve to help reduce nipping directed at other fish. Its deep body offers some protection around larger companions, but should not be treated as a guarantee against predation.

Sexual dimorphism

Males are smaller and slimmer, with more pointed dorsal and anal fins. Females have a fuller abdomen.

Breeding

Both group and pair spawning are possible. Use a separate dim aquarium with fine plants, moss, spawning mops, or protective mesh. Condition adults on quality live and frozen food. For pair breeding, keep the sexes apart beforehand, then introduce a ripe female and a well-colored male; spawning often follows the next morning.

The eggs are adhesive, and parents should be removed promptly because they eat them. Hatching takes about eighteen to thirty-six hours. Free swimming begins a few days later. Start with infusoria-sized food, progressing to microworms and newly hatched brine shrimp. Eggs and early fry are light-sensitive, so keep illumination very subdued.

Notes

Long-finned and pale white-skirt forms are selectively bred varieties. Artificial dye injection is a separate practice that causes substantial stress and can shorten life, so it should not be confused with naturally inherited coloration.