Brycon guatemalensis, the Machaca, is one of the most iconic fish of Central American rivers, occupying Atlantic-slope drainages from Mexico through Guatemala and Belize and into Honduras. It is a large, powerfully built characin reaching 50 cm that is highly valued both as a sport fish and as an important commercial food species across its range. In the aquarium it is a rarely exhibited specialist fish that commands admiration for its imposing size and streamlined silver form.
In captivity, the Machaca requires an extremely large aquarium — 1500 litres minimum — with excellent filtration and high oxygenation. It is an active, fast-swimming open-water fish that needs extensive horizontal swimming space. Water should be moderately hard and slightly alkaline to neutral, reflecting its Central American river habitats. It is an omnivore in the wild, consuming fallen fruits, invertebrates, and smaller fish.
Machacas can be aggressive towards tankmates and are best kept as a single specimen or with fish too large to be threatened. Feeding should include a varied diet of large pellets, fresh fruits, vegetables, and meaty foods such as prawns and white fish. This species is not suitable for typical home aquaria and is strictly for public aquarium collections or the most serious private specialists.
