Aphyosemion loennbergii

Adult specimens reach lengths of 4 to 5 cm. The fish are characterized by a yellow coloration with a distinctive pattern: two dark horizontal stripes are complemented by numerous bright red speckles. Their fins are tall and colorful, displaying gradient transitions from red to yellow and blue. The caudal fin is predominantly blue with visible burgundy veins. Males have more intense and vibrant coloration compared to females. Unlike many other Killifish species, Aphyosemion loennbergii has a longer life cycle and often lives for 3–5 years.

Equatorial Africa is the native land of this species. Individuals of these fish have been found in the Lokundje and Nyong river basins, located in southwestern Cameroon. They prefer to inhabit shallow waters, found in streams and backwaters, hiding among fallen leaves, snags, and branches.

These fish are peaceful and active. Competition for female attention may occur among males. To avoid potential injuries, especially in smaller aquariums, it is recommended to keep these fish in a harem-like setup: one male should be accompanied by 2–3 females. They coexist well with many other species of comparable size.

Aphyosemion loennbergii is not frequently encountered in home aquariums, largely due to breeding difficulties. In artificial environments, these fish exhibit extremely low offspring productivity or do not reproduce at all. However, their maintenance is relatively straightforward. For a group of two or three fish, an aquarium of 40 L or more will be required. When decorating, it is recommended to provide an abundance of aquatic vegetation, including floating species. The substrate should be soft and dark, preferably covered with a layer of fallen leaves, branches, or snags. Soft, slightly acidic water with a temperature between 18–22°C is optimal for them. It is important to avoid using powerful filters that can create excessive current; a simple air-driven sponge filter would be an ideal choice. Aquarium maintenance traditionally includes weekly partial water changes with fresh water and regular removal of organic waste. Although the fish can adapt to most popular foods, their diet must include protein-rich products such as dry, frozen, or live bloodworms, Artemia, and others.

The fish can adapt to most widely available foods. However, it is extremely important to include protein-rich products in their diet, such as dry, frozen, or live bloodworms, Artemia, and similar items.

Breeding this species is considered challenging, as the fish often produce a small number of offspring or refuse to spawn in captivity. Spawning is paired, and it is recommended to keep breeders in a ratio of one male to two or three females. Eggs are laid on fine-leaved plants or substrates that mimic natural conditions. Due to reproduction difficulties, the species is rarely found in wide commercial sale.

The species is sensitive to sudden changes in hydrochemical water parameters and the accumulation of organic waste. The main health problems arise from improper keeping conditions, which provoke the development of bacterial infections and fin rot. Prevention involves maintaining a stable environment, using soft, slightly acidic water, regular water changes, and avoiding strong currents that cause stress to the fish.

When purchasing, choose active fish with clean fins and no visible body damage. It is important to ensure there is no plaque or sores, which indicate diseases. In the store, the fish should exhibit natural caution for the species, but not be excessively timid or apathetic. It is recommended to acquire individuals from the same group, considering their intraspecific competition, and to clarify in advance the keeping conditions to which they have been adapted.