# Congo tetra

The Congo tetra (Phenacogrammus interruptus) is a species of fish in the African tetra family, found in the central Congo River Basin in Africa. It is commonly kept in aquaria.

## Description

The Congo tetra has a typical full-bodied tetra shape with rather large scales. When mature, the iridescent colors of the Congo tetra run through the fish from front to back, starting with blue on top changing to red through the middle, to yellow-gold, and back to blue just above the belly. It is not its fluorescent colors that make this tetra so distinct, but rather its tail fin, which develops into a grayish-violet feathery appendage with white edges. The males get up to 3.0 inches (8.5 cm). Females up to 2.75 inches (6 cm). The male is larger with more color, also the tail fin and dorsal fin are more extended. They also have different colors and extensions in the caudal fin.

## Aquarium trade and keeping

Congo tetra are a popular aquarium species. However, their large size and active behavior makes them unsuited for most smaller tanks. They easily adapt to captive diets like pellets and frozen foods, though they will still hunt down live foods when offered. They have successfully been bred in captivity and captive bred individuals are commonly available. Whilst they can be kept healthy on a slightly wider range of water parameters, breeding often requires water parameters more similar to their natural habitat. Bad water quality has been known to affect male fin development and lead to loss of coloration.

## Disease and care

The Congo Tetra is a moderately hardy freshwater fish. This species thrives in a well-maintained aquarium that mimics its natural, slightly acidic and soft-water habitat. Optimal health for Congo Tetras is achieved in a stable environment with good water quality, a balanced pH level of around 6.0 to 7.5, and temperatures between 72°F and 82°F. A varied diet, including quality flake food, frozen or live brine shrimp, and bloodworms, is essential for maintaining their vibrant colors and overall vitality.
Common diseases affecting Congo Tetras include Ichthyophthirius multifiliis (Ich), a parasitic infection manifesting as white spots on the body and fins, and fin rot, often due to poor water quality. Preventive care is key, emphasizing regular water changes, tank cleanliness, and avoiding overfeeding. Quarantining new fish before introducing them to the main tank is crucial to prevent the spread of diseases. In case of illness, early detection and treatment, often involving specific medications and improved tank conditions, are vital for recovery. Proper care and attention to their environmental needs ensure these stunning fish remain a healthy and dynamic part of any aquarium community.

## Breeding

Congo tetras are egg-scattering fish that exhibit no parental care. They are known to spawn in groups or in pairs, with breeding typically occurring in soft, slightly acidic to neutral water conditions (pH 6.0–7.5) with a temperature range of 75–80°F (24–27°C). A dimly lit environment and the presence of fine-leaved plants or a spawning mop are beneficial, as the species tends to scatter eggs among vegetation.
During courtship, males display intensified coloration and extended fin rays while performing a display to attract females. Once spawning occurs, the female releases several hundred adhesive eggs, which settle among the plants or substrate. The eggs typically hatch within 6 to 7 days, depending on water temperature, and the fry become free-swimming shortly thereafter.
Due to their tendency to consume their own eggs, it is common practice in controlled breeding conditions to separate the adult fish after spawning. The fry require microscopic food such as infusoria or liquid fry food initially, before transitioning to baby brine shrimp and finely crushed flake food as they grow. Growth is relatively fast under optimal conditions, with juveniles developing their characteristic iridescent colors and elongated fins as they mature.
Congo tetras reach sexual maturity at approximately 9 to 12 months of age. Successful breeding in home aquariums can be challenging, often requiring careful monitoring of water parameters and the use of a separate breeding tank to optimize survival rates.

## Conservation status

The IUCN lists the Congo tetra as a species of Least Concern.