Colossoma: Greek, kolos = short, truncated + Greek, soma = body
Pacu grow very big and are capable of causing a serious injury through biting. These fish are best left for public aquariums where they can be properly housed and cared for. Very few home aquaria are capable of housing an adult pacu. Their size apart pacu are extremely tolerant of a wide range of conditions and are very hardy. A fairly bare tank with perhaps one or two branches for decor is all that is needed, any plants will simply be eaten. Large fish will be left alone because pacu's are not aggressive but small fish may be regarded as food. Pacu's as mentioned are not really aquarium fish, but sadly they are often seen for sale at two or three inches and may be purchased out of ignorance.
Pacu's are essentially herbivores. They feed on nuts, grains, aquatic plants but they will also eat smaller fish and insects when they can. In captivity they are unfussy feeders but their diet should contain fresh greens with lots of fibre.
Females are said to be a little more plump when adult but this can't be relied upon as a guaranteed way of determining the sex of these fish.
Pacu have not been bred in captivity by hobbyists but they have been bred commercially with the use of hormones.
Pacu are widespread due to introductions beyond their natural range. But the status of wild populations has not been evaluated.
pH: 5 - 7.8
dGH: 2 - 20
Temperature: 22 - 28°C (72 - 82°F)
Size: 70cm+ (28in+)
Min tank size: - litres
Difficulty level: Do not keep
Aquarium type: Community
Swimming level: Middle
Origin: South America: Amazon and Orinoco basins
Habitat: Adults stay in flooded forests during first 5 months of flooding and consume but fruits and grains. Young and juveniles live in black waters of flood plains until their sexual maturity
Species: C. macropomum (Cuvier, 1816)
Synonyms: Myletes macropomus, Piaractus macropomus, Salmo tambaqui, Myletes oculus, Colossoma oculus, Myletes nigripinnis, Colossoma nigripinne, Melloina tambaqui, Colossoma tambaqui