Agassiz's dwarf cichlid

Water parameters

Tolerated range for this species. Aim for the middle of each band rather than the extremes.

Tank and habitat

Substrate: sand.

Behavior

Plant interaction: plant safe.

Typically wild-caught; acclimate slowly.

Feeding

Carnivorous-leaning omnivore. The preferred foods are frozen bloodworm, frozen brine shrimp, frozen daphnia, live blackworms, and live baby brine shrimp. High-quality micro pellets and some flake are accepted, but live and frozen food bring out the best colour and breeding behaviour. Feed twice a day. The male tends to be bolder than the female at feeding time, and a female stuck behind a possessive male sometimes needs food delivered directly to where she is, not the usual drop zone.

Compatibility

• A harem breeder. One male with two or three females in a planted tank with several caves and broken sightlines is the standard setup. Two males in the same tank requires considerably more floor area and visual separation, or the loser ends up cornered
• Outside of the immediate breeding territory the male is fairly tolerant of unrelated species. The defended zone is small
• Avoid mixing with other dwarf cichlids. Better tankmates are peaceful upper-water schoolers such as small tetras or pencilfish. Bottom dwellers like otocinclus or small corydoras usually coexist fine, though some bottom fish will pick off fry
• Not reliably shrimp-safe. Adult shrimp are sometimes ignored, but shrimplets are eaten and some fish hunt small shrimp actively

Origin and habitat

A dwarf cichlid widespread across the upper-to-middle Amazon. Its range covers Peru and Brazil along the main Solimoes-Amazon channel and its tributaries, from the Maranon and Ucayali in Peru downstream as far as the Capim river near the Atlantic delta. That distribution is unusually broad for the genus: of the roughly 90 to 100 Apistogramma species currently recognized, only a handful (this one, A. cacatuoides, A. bitaeniata) cover anything close to that area, while most are tied to a single river system. The species was originally placed in Geophagus when Steindachner described it in 1875 (as Geophagus (Mesops) agassizii); the lectotype came from Lake Manacapuru, in Amazonas state, Brazil. The species honors the naturalist Louis Agassiz, who led the Thayer Expedition of 1865 and 1866, during which the type material was collected. The genus name is built from Greek apistos (doubtful) and gramma (something written), a reference to the variable, often incomplete lateral line. In the wild it sticks to shallow, slow water with a layer of leaf litter and plant debris on the bottom, across clear, blackwater, and whitewater habitats; that range is part of why local populations look so different from each other, and aquarium strains carry names such as fire red, gold, and blue. A 2020 paper (Estivals et al., Aquatic Conservation 30:1521-1539) found at least three distinct genetic clusters within what is currently labelled A. agassizii in just one stretch of the Peruvian Amazon, and the authors suggested the name probably covers tens of species rather than one. Adult males grow to about 8 to 9 cm, females to about 5 to 6 cm. IUCN Least Concern.

Breeding

Spawns in caves with female-led brood care. The male holds a territory containing one or more potential spawning sites such as coconut shells, clay pots, or natural cavities in driftwood; the female selects and cleans the one she wants and lays adhesive eggs on the upper surface inside. Reported clutch sizes vary widely, from a couple of dozen to a couple of hundred; one study put the range at 20 to 250 with an average around 120 to 140. The male only enters the cave briefly to fertilize, after which the female takes over fanning and guarding the eggs while he patrols the perimeter. Hatching takes about 2 to 3 days depending on temperature, with the fry going free-swimming roughly a week after spawning and trailing the mother in a tight cluster. She signals to them by flicking her body and changing the pattern of black bars on her flanks. Out of breeding condition, females are a fairly drab grey-brown; in brood colour they turn intense yellow with bold black markings. The fry start on baby brine shrimp and microworms. In a small tank the male is best removed once spawning is complete, since a brooding female will chase him hard and can kill him if he has nowhere to retreat to.

Common problems

Apistogramma in general are more sensitive to ammonia and nitrite than the average community fish, so a fully cycled tank and consistent water changes that keep nitrate low matter more here than they do for the usual tetra setup. The species prefers soft and slightly acidic water (around pH 6.0 to 7.0, GH below 10); harder, more alkaline conditions stress them, reduce lifespan, and tend to stop eggs from developing. Hexamita, the flagellate associated with hole-in-the-head erosions, white stringy faeces, and a hollow look across the belly, shows up when water quality slips or the diet is too monotonous; the standard response is to improve conditions and treat with metronidazole. Internal parasites are common in wild-caught stock and can cause gradual wasting in fish that are still eating, so quarantine new arrivals and treat with an antiparasitic such as praziquantel. The most important social problem is male aggression toward females in a tank that is too small or has too few hiding places: a female with no way to break the male's line of sight will be harassed to death. Always provide more caves and sightline breaks than seems necessary.

Bioload

Further reading

• How to cycle a fish tank
• Stocking ideas by tank size