Cochu's Blue Tetra

Geographical Origin and Habitat: Boehlkea fredcochui is native to the Amazon River basin in South America, with populations concentrated primarily in the upper Marañón River basin in Peru. It inhabits main freshwater rivers, secondary channels, forest streams, and flooded areas during the rainy season. It prefers flowing, well-oxygenated waters, often in areas with dense riparian vegetation and submerged roots.

Taxonomy and Morphology: Belonging to the family Characidae, it exhibits a slender, fusiform, and moderately compressed body profile typical of active characin swimmers. It features a well-defined adipose fin and a slightly upturned mouth lined with small teeth. Adults reach a maximum total length of approximately 4.0 to 5.0 centimeters.

Social Behavior: A schooling, highly active species that must be kept in groups of at least 8 to 10 individuals to ensure their well-being and diffuse their energetic swimming behavior. They can display nippy behavior if kept in cramped conditions or in small groups, tending to nip the fins of slower, long-finned tankmates.

Coloration and Sexual Dimorphism: The coloration is magnificent and distinct, featuring a body entirely covered in metallic electric blue reflections that stand out under proper lighting. The fins are mostly transparent, with the caudal fin showing dark highlights. Males are more slender and display brighter blue colors, while females are noticeably plumper during the breeding season.

Aquarium Setup: Requires a freshwater aquarium of at least 100 liters (approx. 25 gallons). The tank must provide ample open swimming space in the center to accommodate their fast swimming, combined with dense planting along the sides and back to offer shelter. Floating plants to diffuse lighting and a dark substrate are recommended to enhance their blue coloration.

Diet and Feeding: Omnivorous and opportunistic feeder. In the aquarium, they readily accept high-quality dry flakes and micro-pellets. To maintain optimal health and color, supplement their diet regularly with small live or frozen foods such as daphnia, brine shrimp, bloodworms, and cyclops.

Water Quality: Prefers soft, acidic water. Ideal water parameters are a temperature of 22°C to 27°C, pH between 5.5 and 7.0, and general hardness (GH) between 2 and 10 dGH. Efficient biological filtration is necessary, with moderate to strong water currents to simulate their natural river habitat. Perform regular partial water changes.

Compatibility and Cohabitation: Suitable for community tanks with active, robust tankmates. Compatible species include other active tetras, danios, rasboras, Corydoras catfish, and peaceful dwarf cichlids. Avoid housing them with slow-moving or long-finned fish (such as Betta splendens or Guppies) that may fall victim to fin-nipping.

Aquarium Breeding: Breeding is possible but requires a separate breeding tank. They are egg scatterers, depositing adhesive eggs among fine-leaved plants in soft, acidic water (pH 5.5-6.0) under low light. Parents must be removed immediately after spawning to prevent egg consumption. Fry hatch in 24 hours and feed on infusoria initially.

Risks and Diseases: They are sensitive to sudden changes in water parameters and high nitrate levels. Prone to freshwater white spot disease (Ich) if exposed to temperature shocks or stress. Inadequate tank size or small school sizes will significantly increase their fin-nipping behavior.