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

The Black Morpho Tetra is a small, elegant characin with a dark brown to blue-black body, delicate iridescent highlights and contrasting pale markings on the fins. Its subdued colours can deepen dramatically when the fish feels secure, making it especially attractive under subdued aquarium lighting. Mature males often display the strongest contrast and the most extended fin rays.

This species is peaceful but not passive. Males may establish small territories around caves, roots or leaf litter, while groups spend much of their time moving quietly through shaded areas rather than forming a constantly tight shoal in open water. Their reserved nature makes them more rewarding in a calm, thoughtfully arranged aquarium than in a busy community.

In the wild, Black Morpho Tetras inhabit clear to heavily tannin-stained forest creeks and small tributaries. These waters are typically slow flowing, soft and acidic, with a bottom covered by fallen leaves, fine branches and patches of submerged vegetation. The dark surroundings provide both shelter and the conditions in which their subtle colouration is most visible.

Poecilocharax weitzmani belongs to the small South American crenuchid family, a group of characins that includes several cryptic stream-dwelling species. It is sometimes overlooked in favour of brighter tetras, but its intricate markings, fascinating social behaviour and unusual breeding habits have made it a sought-after choice for specialist aquarists.

Black Morpho Tetras are native to forest streams and tributaries of the upper Amazon and Rio Negro drainage in northern South America, particularly areas of Brazil, Colombia and Peru. They are associated with shaded, slow-moving blackwater habitats rich in submerged wood, leaf litter and tannins.

A group should be kept in an aquarium of at least 60 litres, with a footprint around 60 by 30 cm or larger. Use gentle filtration and subdued lighting, with driftwood, small roots, caves, dried leaves and clumps of fine-leaved plants creating broken sight lines and shaded retreats. A dark, soft sand or fine-gravel substrate complements their colours and allows leaf litter to be used safely. Stable, clean, very soft water with mild tannins and moderate oxygenation suits their forest-stream origins.

Up to 4 cm (1.6 inches) in length. Males are usually slightly larger and more elongated than females.

They are small micropredators that naturally feed on tiny aquatic invertebrates and other minute prey. Offer a varied diet of newly hatched brine shrimp, daphnia, cyclops, grindal worms and suitably sized frozen foods, supplemented with a high-quality micro-pellet. Small live foods are particularly useful for conditioning adults and encouraging shy or newly imported fish to feed.

Black Morpho Tetras suit peaceful communities of similarly sized, gentle fish. Good companions include small pencilfish, ember or green neon tetras, peaceful small rasboras, Otocinclus and dwarf Corydoras. Avoid large or boisterous fish, fin-nippers and aggressive species, which can keep them hidden and outcompeted. Adult dwarf shrimp may coexist in a well-structured aquarium, although newly hatched shrimp will likely be eaten.

Black Morpho Tetras are cave-spawning fish. Provide several small caves, pieces of leaf litter and shaded spawning sites, then condition the adults with abundant live or frozen foods. A male may defend a cave and guard the eggs after spawning. Once the eggs hatch, the tiny fry need very small first foods such as infusoria before they can accept newly hatched brine shrimp. Separating the fry from the adults improves survival.

Males are generally slimmer, slightly larger and more intensely marked, with longer or more pronounced fin rays, especially when displaying. Females have a fuller abdomen when mature and usually show shorter, less extended fins.