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Fish Freshwater Care: medium Aggressive

Bucktooth Tetra

Exodon paradoxus
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Other names: Exodon, Scale-eating tetra
Group: Tetras and characins · Family: Characidae · Origin: South America — Amazon and Tocantins basins (Brazil), Guyana

An aggressive tetra known for the two large black spots on its body that, in the wild, tears off and eats the scales of other fish. It should only be kept in a large group in a species-only tank.

Will it suit my tank?

Last updated October 16, 2026

Temperature
23–28°C
pH
5.5–7.5
Hardness
2–15 dGH
Adult size
12 cm
Minimum tank size
250 liters
Lifespan
6–10 years
Social structure
School
Group
at least 10, ideally 15+
Swimming zone
Middle
Diet
Carnivore
Breeding
Egg scatterer

Water parameters

Temperature23–28°C
pH5.5–7.5
General hardness (GH)2–15 dGH
Recommended range
Fin nipper Eats small fish Eats shrimp Suitable for planted tanks

Overview

October 16, 2026 · Suggest an edit

The bucktooth tetra is a good-looking species with two large, round black spots on its yellowish-silver body, one at the shoulder and the other at the base of the tail, and reddish fins. In the wild, however, it feeds by tearing off and eating the scales of other fish (lepidophagy). It is a very fast, aggressive tetra that can exceed 12 cm; it is not suitable for a community tank.

Tank Setup

October 16, 2026 · Suggest an edit
  • At least 250 liters for a group of 10 or more; 120 cm length.
  • 24–27°C, pH 6–7.5, soft to moderately hard water.
  • Plenty of decor that breaks lines of sight (roots, rocks, sturdy plants) spreads out aggression.
  • Strong filtration and a lid are recommended.

Diet

October 16, 2026 · Suggest an edit

Mainly carnivorous. Carnivore granules, frozen bloodworms, mysis shrimp, brine shrimp and strips of fish meat are suitable. Feeding it well reduces attacks on other individuals.

Behavior and Compatibility

October 16, 2026 · Suggest an edit

When kept in small numbers, the dominant fish can badly batter the others; so it should be kept either in a large group or not at all. It attacks the scales and fins of other fish kept with it; it eats small fish and shrimp.

Good companions: ideally only its own species; armored plecos in very large tanks.

Avoid: almost all community fish, slow and long-finned species, shrimp.

A short profile for this species

The Bucktooth Tetra page has the basics, but the sections below have not been written yet. If you keep this species, write a section from your own experience; it will be published under your name after editor approval.

Tank mates

This list is calculated automatically from the species profile and grows as new species are added to the catalog. Try it in the planner for a definite answer.

Usually compatible

Should not be kept together

Hobbyist notes

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Change history and contributors
  1. Page created · October 16, 2026