Slender Hemiodopsis

Adults reach 15 cm in length. They have a slender, elongated body in silvery tones, marked by a black horizontal stripe that runs from just behind the dorsal fin along the tail, curving elegantly along its lower edge. A bright red mark is also visible on the lower rim of the tail fin. The dorsal, ventral and anal fins are short and triangular in shape. This body structure identifies the slender hemiodopsis as a fast swimmer, capable of sudden bursts of speed.

This fish is found in South America, in the rivers and lakes of Brazil and Venezuela. They inhabit backwaters of large rivers and numerous lakes in the tropical forests of the Amazon.

These are peaceful and friendly fish, highly active in a way that may disturb some quieter species. They do well with Amazonian cichlids, catfish, and other characins of similar size and temperament.

This species needs considerable swimming space, so the tank should be at least 250 litres. Use any sandy substrate and include several pieces of wood, twisted roots or branches, plus rooted and floating plants. Create several hiding spots from these elements, as the slender hemiodopsis is rather shy despite its reasonable size and will retreat when alarmed. Pay close attention to water quality: keep organic waste to a minimum and maintain a high oxygen level. Other important factors are a temperature range of 23–27 °C, slightly acidic pH, and low to moderate water hardness. Choose equipment to meet all these requirements. The tank must also have a tight-fitting lid to prevent the fish from jumping out.

Their diet can include all appropriately sized dry, frozen and live foods. Supplement with plant matter, varying the diet by combining different foods such as dry flakes, bloodworm and spirulina tablets.

There are no reliable reports of the slender hemiodopsis breeding successfully in aquarium conditions. Most fish offered for sale are imported as juveniles from the wild or from specialist farms.

The main threat to their health is unsuitable conditions, including incorrect pH, water hardness, temperature and other parameters, as well as high pollution levels. At the first signs of illness (lethargy, loss of appetite, unusual growths on the body), check all water parameters at once and adjust them if needed. Such steps are often enough to restore the fish to health.

When buying, choose fish with clean fins and undamaged scales, as this species is prone to injury during transport. Check that the fish swim actively and behave as a group, avoiding thin individuals or those with an unusually swollen belly. The fish are naturally shy and may appear sluggish in the shop, but healthy specimens should respond to movement near the tank. It is best to buy a group of 6–10 at once, as keeping single fish causes severe stress and loss of appetite.