Black Skirt Tetra Care Guide - Aquarium Setup, Diet & Breeding

The Black Skirt Tetra is a deep-bodied, laterally compressed characin with a silvery-grey front half and two prominent vertical black bands behind the gill cover. Its tall dorsal fin and long, skirt-like anal fin give the species its familiar common name, while the fins often become paler and more translucent with age.

These active fish are known for their lively schooling behaviour and constantly changing group formations. They are generally peaceful, although individuals may occasionally nip at the fins of slow-moving or long-finned companions, particularly when kept in an undersized group or cramped aquarium.

In the wild, Gymnocorymbus ternetzi is associated with warm, slow-flowing waters containing submerged roots, aquatic plants and leaf litter. The combination of cover and open swimming areas allows the fish to move through vegetation while remaining alert to predators.

Black Skirt Tetras have been popular in the aquarium hobby for decades and are also available in selectively bred colour and fin forms. The standard natural form remains especially valued for its bold striped pattern, energetic personality and suitability for a well-planned community aquarium.

Black Skirt Tetras are native to South America, particularly the Paraguay and Paraná river basins in southern Brazil, Paraguay and northeastern Argentina. They inhabit slow-moving rivers, tributaries, flooded areas and forested waters with vegetation and subdued light.

A group of Black Skirt Tetras should have at least a 75-litre aquarium, with a footprint of around 60 × 30 cm or larger and enough length for active swimming. Use a dark or neutral fine-grained substrate, areas of dense planting, floating plants and driftwood or smooth branches to create shaded retreats while leaving an open central area. Gentle to moderate circulation, stable water quality and subdued or broken lighting suit their natural preference for sheltered, vegetated habitats.

Up to 5.5 cm (2.2 in) in standard length. Females are usually slightly larger and deeper-bodied than males; males typically remain a little slimmer and may reach around 5 cm (2 in).

Black Skirt Tetras are omnivores and thrive on a varied diet. Offer a quality tropical flake or small micro-pellet as the staple, supplemented with frozen or live foods such as brine shrimp, daphnia, mosquito larvae and bloodworm. Small portions of food should be provided regularly, with variety helping maintain colour, condition and breeding readiness.

Black Skirt Tetras can share an aquarium with other similarly sized, peaceful community fish, including larger rasboras, danios, peaceful barbs, rainbowfish, Corydoras, smaller plecos and many non-aggressive gouramis. Keep them away from very small, timid species that may be intimidated by their activity, as well as slow-moving fish with elaborate fins such as bettas and fancy guppies, which may be targets for fin nipping. They should not be housed with large predatory fish or aggressive cichlids.

Black Skirt Tetras are egg-scattering fish that spawn readily when conditioned with varied, nutritious foods. Set up a separate breeding aquarium with soft, slightly acidic to neutral water, gentle filtration and fine-leaved plants or a spawning mop. A conditioned pair or small group usually spawns among the plants, scattering adhesive eggs. Remove the adults after spawning because they may eat the eggs. The eggs generally hatch within 24 to 36 hours, and the tiny fry can be raised on infusoria or other suitably fine first foods before progressing to baby brine shrimp.

Females are generally larger, fuller-bodied and more rounded through the abdomen, especially when carrying eggs. Males are usually smaller and slimmer, with a more streamlined profile; their fins may also appear comparatively more elongated.