Red Ornate Tetra

This species is closely related to the rubrostigma and Sokolov's tetra, which explains their similar appearance. Adults reach about 4 cm in length and display colouration ranging from pink to orange-red. Females are typically lighter and appear fuller, especially before spawning. Males are brighter, with elongated anal and dorsal fins, and the tip of the dorsal fin is dark. A red spot behind the gill cover is a characteristic mark of this group.

The red ornate tetra comes from South America, particularly the Rio Negro basin (Amazonas state, Brazil), the largest left tributary of the Amazon. A wider natural range is suspected. The fish inhabit small river and stream systems flowing through dense tropical forests. Typical habitat is shallow streams with bottoms scattered with wood debris such as roots and branches, overhanging riparian vegetation, and abundant aquatic plants. The substrate is usually sandy, covered with a layer of fallen leaves. The water takes on a rich brown colour due to high levels of organic matter.

These active fish are peaceful and do well with other species of similar size. A school of at least 8–10 individuals is recommended. Under these conditions, males competing for females will display their most vibrant colours.

A school of 8–10 red ornate tetras requires a tank of at least 60 litres. Although these fish adapt well to various conditions, it is best to set up their tank to mimic their natural habitat. The long-finned ornate tetra looks best in a space with plenty of aquatic plants and wood, and dimmed lighting benefits them. Placing dried leaves on the bottom is a useful addition: as they decompose, they enrich the water with tannins, bringing its chemical composition closer to natural conditions and giving it a characteristic brown tint. These leaves also serve as a substrate for developing colonies of microorganisms such as paramecia, which are an important food source for fry. Maintaining high water quality is key to successful keeping. This means preventing the buildup of organic waste, keeping water chemistry within acceptable parameters, and performing regular partial water changes. The ecological balance of the tank is also closely tied to effective filtration and other water treatment equipment.

This undemanding fish readily accepts most common aquarium foods in captivity. Diet has a direct effect on colour intensity and overall health, so quality products from trusted manufacturers are preferable.

In artificial conditions, several generations of these fish have lost their seasonal breeding traits, allowing them to reproduce year-round. In a large school of dozens of fish, it is likely that several will enter spawning condition each month. Breeding occurs by scattered egg-laying across the substrate. This process is disorderly, with no localised spawn formed; fertilised eggs end up randomly distributed across the bottom. These fish lack parental instinct; adults show no care for offspring and may eat their own eggs and fry. To ensure fry survival, move them to a separate tank.

No species-specific diseases have been recorded in this fish. When optimal keeping conditions are maintained—high water quality, balanced feeding, and no aggressive tank mates—health problems are usually absent. Poor conditions, which weaken the immune system, are the most common cause of disease, making fish vulnerable to infections already present in the environment. If signs of illness appear, such as lethargy, wasting, loss of appetite, or drooping fins, check water parameters immediately. Restoring acceptable conditions often leads to natural recovery. However, if the fish is severely weakened or has visible damage, medication may be needed.

When selecting fish, pay attention to their activity and skin condition. Healthy fish school together, have clean scales with no visible spots, sores or coating, and clear, undamaged fins. Avoid fish that look emaciated, stay apart near the surface or bottom, or show rapid breathing. — Check for visible parasites on body and fins. — Make sure the fish show interest in food when fed in front of you. — Inspect the shop tank: dead fish in a display tank is a bad sign. — Because of resemblance to related species, confirm correct identification by the characteristic red spot behind the gill cover and fin shape.