Costa's Tetra Care Guide - Aquarium Setup, Diet & Breeding

Costa's Tetra is a small, lively characin with a slender, silvery body and a subtle golden to olive sheen. Its translucent fins and dark markings near the rear of the body give it a neat, understated appearance, while a healthy shoal becomes increasingly attractive as the fish move together through the aquarium.

This species is active and peaceful, spending much of its time in the middle levels of the water column. It is more confident and displays more natural social behaviour when kept in a proper group, where the fish may school closely when startled before spreading out to explore.

In the wild, Costa's Tetra inhabits warm freshwater streams and tributaries in northeastern Brazil. These waterways can experience pronounced seasonal changes in flow and water conditions, and the surrounding landscape is often shaped by the dry caatinga environment.

Although it is not as widely kept as some brightly coloured tetras, Moenkhausia costae is a rewarding choice for aquarists who enjoy active South American schooling fish. Its manageable size, peaceful temperament and constant movement make it well suited to a thoughtfully planned community aquarium.

Costa's Tetra is native to northeastern Brazil in South America, particularly river systems associated with the São Francisco basin and nearby coastal drainages. It occurs in warm, seasonally variable freshwater habitats, including streams and smaller tributaries in the semi-arid caatinga region.

A group of Costa's Tetras should be given at least a 60-litre aquarium, with a footprint around 60 x 30 cm or larger and enough open swimming space for active midwater movement. Use a secure cover, gentle to moderate water movement and efficient filtration without creating excessive turbulence. A dark or neutral fine substrate, shaded areas, driftwood, smooth stones and live plants around the sides and rear create a natural-looking layout while leaving the centre open. Floating plants or subdued lighting can help the fish feel secure and show off their schooling behaviour.

Approximately 5 cm (2 inches) maximum adult length. Females are usually slightly larger and deeper-bodied than males, while males tend to remain a little slimmer.

Costa's Tetras are omnivores and do best on a varied diet of quality small flakes or micro-pellets supplemented with frozen or live foods. Offer foods such as baby brine shrimp, daphnia, cyclops and mosquito larvae in suitably small portions. Regular variety helps maintain their colour, activity and condition, while feeding should be limited to what the group can consume promptly.

Costa's Tetras can be kept with other peaceful fish of a similar size, including small South American tetras, pencilfish, peaceful rasboras, Corydoras, small peaceful loricariid catfish and suitable dwarf cichlids. Avoid large predatory fish, highly aggressive species and notorious fin-nippers, which may intimidate or injure them. Very slow-moving or long-finned fish are also best chosen with care because this tetra is an active swimmer.

Costa's Tetras are egg-scattering characins that can be bred in a separate, dimly lit breeding aquarium. Condition a group with plenty of live or frozen foods, then introduce a pair or small group when the females are full of eggs. Fine-leaved plants or spawning mops provide surfaces for the eggs, which are scattered among the vegetation. Remove the adults after spawning because they may eat the eggs. The eggs usually hatch within a day or two, and the tiny fry can be raised on infusoria or other suitably fine first foods before moving on to newly hatched brine shrimp.

Females are generally fuller through the abdomen, especially when carrying eggs, and may be slightly larger overall. Males are typically more slender and can appear a little more streamlined, although the differences are subtle outside of mature, well-conditioned fish.