鹿齿鱼 · Bucktooth Tetra

Overview

Exodon paradoxus uses specialized teeth to remove scales from other fishes. It is unsuitable for an ordinary community aquarium. A large dedicated group can be visually striking, but managing aggression, filtration, and refuges is essential.

Distribution & habitat

It is widespread in the Brazilian Amazon, with additional records toward Guyana. Typical habitat is flowing river water over sand in grassland-like landscapes.

Aquarium setup

Sand, roots, and branches provide a naturalistic base. Dense planting offers escape cover for fish receiving unwanted attention. Filtration must cope with the feeding and waste load of a substantial group. Restricted space leaves subordinate fish especially vulnerable.

Diet & feeding

Stomach studies show insects and fish scales as major wild foods. Live fish are unnecessary in captivity: bloodworms, chopped shrimp, mussel, earthworms, and fish flesh are readily used, and most individuals take dry food too. Feeding is forceful and competitive, so any companions must be checked for adequate intake.

Behaviour & compatibility

A species aquarium is strongly preferable. Reflective or silver fishes can be persistently stripped of scales and fins, even when larger or predatory themselves. Scaleless or nonreflective companions sometimes succeed, but compatibility remains unpredictable.

Begin with at least twelve and maintain a large enough group for the available aquarium and filtration. Small groups may be reduced through repeated attacks to a single survivor. Larger groups spread the aggression, although losses of unhealthy fish and occasional others remain possible. Acquire the group together, as later additions are often attacked.

Sexual dimorphism

Mature males are slimmer and tend to have slightly extended dorsal and anal fin rays.

Breeding

This egg-scattering species has been bred only occasionally. Prepare a separate aquarium with soft, mildly acidic water and fine plants or mesh to protect the eggs. Condition the adults within their shoal, then move a selected pair. A large change using slightly warmer water has reportedly sometimes triggered spawning.

Remove parents when eggs appear. Hatching takes two or three days. Rearing details are sparse; small live foods such as newly hatched brine shrimp are likely suitable. Cannibalism among the young is expected to be a concern, so watch growth differences and prepare additional rearing space.