Phoenix rasbora

Geographic Origin and Biotope: Endemic to the Jelai and Kahayan river basins in southern Borneo (Indonesia). Inhabits peat swamps where dark, slow-moving water makes its way through submerged roots and dense blankets of organic material.

Taxonomy and Morphology: Phoenix Rasbora (Boraras merah). "Merah" in Indonesian means "red". Very similar to B. brigittae with which it is sympatric (they live in the same habitat and are often caught together), but it has a broken lateral pattern instead of a solid line.

Social Behavior: Of an extremely gregarious nature, it must live in schools formed by a minimum of 15-20 individuals. In smaller groups it will become apathetic, lose its colors and tend to hide perpetually under the leaves.

Coloration and Sexual Dimorphism: Reddish-orange background (less intense than the blood-red of brigittae). In the center of the body there is a large dark oval spot, surrounded by a bright red halo (hence the name Phoenix), followed by disjointed black spots towards the tail.

Aquarium Setup: Ideal for a 20-30 liters (5-8 gallons) Nano-cube. Needs a densely planted "Blackwater" layout, with a dark sand or soil bottom, abundance of woods and very light mechanical filtration. Amber water through alder cones.

Diet and Feeding: In nature it hunts microorganisms in the dense foliage. In the aquarium, the staple food must be tiny live food: brine shrimp nauplii, microworms and daphnia. Accepts powdered dry food but in the long run it fades the coloration.

Water Quality: The ideal water is very soft and acidic (pH 4.0-6.5), amber and rich in tannins to prevent bacterial infections. An increase in nitrogenous compounds is lethal to the species.

Compatibility and Tankmates: Perfect in a dedicated tank. Excellent tankmate for Neocaridina, small Otocinclus, and dwarf Corydoras. Categorically avoid active fish over 4 cm (1.5 inches) in size, which could mistake it for food.

Aquarium Reproduction: Continuous spawner that scatters a few eggs daily among mosses (Taxiphyllum). The eggs are lucifugous (they fear strong light). If the tank is dense and mature, a few fry will survive without care.

Risks and Diseases: Threatened in the wild by rapid urbanization and the conversion of its habitat into rubber and palm oil plantations. In the aquarium, it risks being sucked into the filter and occlusions if fed with food that is too large.