Foirni Checkerboard Cichlid (Dicrossus foirni)

Geographic Origin and Biotope: Middle and upper Rio Negro basin, in Brazil. Inhabits ultra-acidic waters (pH below 5), surrounded by piles of wood and roots in flooded rainforest rivers.

Taxonomy and Morphology: Foirni's Checkerboard Cichlid (Dicrossus foirni). Often labeled as Dicrossus sp. "Rio Negro" in the past. It is the most massive and voluminous species of the genus Dicrossus.

Social Behavior: Relatively shy, moves constantly but jerkily among the dead leaves. Being larger than the "filamentosus", males can show themselves moderately intolerant towards conspecifics if space is scarce.

Coloration and Sexual Dimorphism: Gorgeous. Beige background covered by "checkerboard spots", but in foirni the checkerboards tend to partially merge or are framed by incredible metallic blue and blood red reflections on males. Round tail, not lance or fork-shaped.

Aquarium Setup: Long aquarium required (at least 100 cm / 40 inches). White silica sand, woods of intricate branches (manzanita wood), abundant leaf litter and total absence of intense lighting. Add alder cones for tannin.

Diet and Feeding: They need a weaning phase. Offer Grindal worms, fine bloodworms and brine shrimp (live or very high quality frozen). Once acclimatized, they are able to collect micro-pellet food from the bottom.

Water Quality: "Blackwater Extreme" fish. Stable temperature (27-28°C / 81-82°F), pH between 4.0 and 5.5, non-existent hardness and conductivity close to 10 µS. Nitrates must be absolute 0.

Compatibility and Tankmates: Ideal companions are small characins (Hemigrammus bleheri, Paracheirodon axelrodi) and surface fish. Strongly not recommended other bottom cichlids so as not to crack its reserved psyche.

Aquarium Reproduction: A real milestone for the demanding aquarist. They lay on catappa leaves. The female becomes a protective fury and will assume war coloration. Very delicate eggs subject to fatal mold if the pH rises above 5.

Risks and Diseases: Sensitivity to "fresh water" pathogens. In Blackwater rivers the bacterial load is zero. In aquariums without tannins or with high GH/KH, they are quickly decimated by skin ulcers and dropsy.