Bucktooth Tetra (Exodon)

Exodon paradoxus

Characins

The Bucktooth Tetra is a highly active, predatory shoaling fish infamous for its scale-eating (lepidophagous) behavior. They are extremely aggressive and will strip the scales, fins, and even eyes off almost any tankmate. They must be kept in a species-only tank in large groups (12+) to disperse their intense conspecific aggression; otherwise, they will systematically kill each other.

At a Glance

Adult Size12 cm
Body ShapeFusiform
Growth RateModerate
TemperamentHighly Aggressive
Water TypeFreshwater Only
Flow PreferenceModerate
Waste OutputMedium
StockingSchool of 12+

Tank Requirements

Minimum Volume200 L
Minimum Length120 cm
FlowModerate
Water TypeFreshwater Only
Must-Haves in the Tank
Driftwood (Digestion/Hiding)

Water Parameters

Temperature2328°C
pH5.57.5
Hardness115 dGH

Temperament & Compatibility

Aggression LevelHighly Aggressive
9/10
Where They Swim
Surface
Mid-level
Bottom
Stocking Guidelines
Keep at Least12 fish
Max per TankNo limit
Can Live Alone?No — needs a group
Behavior Traits
Generally AggressiveAggressive to same species/look-alikesFin NipperPiscivore (Eats small/nano fish)Hyperactive / Fast SwimmerEye Biter (Attacks slow moving fish)Jumper (Lid Required)

Available Varieties

Each variety inherits the species defaults above. Only differences are highlighted.

Standard

The standard Bucktooth Tetra. Must be kept in a large species-only aquarium. Do not attempt to house with other species, including heavily armored bottom dwellers, as they will relentlessly attack them. A tight-fitting lid is required as their frantic feeding and chasing behavior often leads to jumping.

Differs in 1 trait from base species

Also known as: Wild Type

Behavior Traits
Generally AggressiveAggressive to same species/look-alikesFin NipperPiscivore (Eats small/nano fish)Hyperactive / Fast SwimmerEye Biter (Attacks slow moving fish)Jumper (Lid Required)

Bucktooth Tetra (Exodon) Care Guide Summary

The Bucktooth Tetra (Exodon), scientifically known as Exodon paradoxus, belongs to the Characins family group. Adults reach a maximum size of approximately 12 cm and have a fusiform body shape with a moderate growth rate. Classified as highly aggressive, this species primarily occupies the mid-level and surface zones of the aquarium and produces a medium level of biological waste.

To thrive, the Bucktooth Tetra (Exodon) requires a freshwater only aquarium with a minimum volume of 200 litres and a tank length of at least 120 cm. Water temperature should be maintained between 23°C and 28°C, with a pH range of 5.57.5 and a general hardness of 115 dGH. A moderate water flow is preferred.

Due to its specialist needs, the Bucktooth Tetra (Exodon) is best suited for fishkeepers who can provide a carefully planned setup. The Bucktooth Tetra (Exodon) is typically available in one standard form.

Bucktooth Tetra (Exodon) Habitat Setup

When setting up an aquarium for the Bucktooth Tetra (Exodon), a moderate water flow best suits their natural preferences. Because this species occupies the mid-level and surface zones, the aquarium layout should prioritise adequate surface area with floating cover to make them feel secure near the waterline and open swimming space in the centre of the tank for free movement. Useful additions include driftwood, which can serve as both a hiding place and a dietary supplement. Keepers should note that a tight-fitting lid is essential, as this species is a known jumper.

Bucktooth Tetra (Exodon) Compatibility Notes

Classified as highly aggressive, the Bucktooth Tetra (Exodon) is a schooling species that feels most secure in a sizeable group, where natural shoaling behaviour reduces stress and brings out their best colours. When choosing tankmates, avoid housing with slow-moving or long-finned species that may become targets for fin nipping, any fish small enough to fit in its mouth will likely be eaten, conspecific aggression can be intense, especially in smaller tanks, and their energetic swimming style may stress more sedentary or timid species. Selecting tankmates that favour different water layers from the mid-level and surface zones can help reduce competition and territorial overlap.

Frequently Asked Questions About Bucktooth Tetra (Exodon)

How big does Bucktooth Tetra (Exodon) get?+
Bucktooth Tetra (Exodon) (Exodon paradoxus) typically reaches a maximum adult size of approximately 12 cm. They have a fusiform body shape and a moderate growth rate.
What tank size does Bucktooth Tetra (Exodon) need?+
A minimum aquarium volume of 200 litres and a tank length of at least 120 cm are recommended for Bucktooth Tetra (Exodon). This ensures enough swimming space and helps maintain stable water conditions.
What water parameters does Bucktooth Tetra (Exodon) need?+
Bucktooth Tetra (Exodon) thrives in freshwater only conditions with a temperature range of 23–28°C, a pH between 5.5 and 7.5, and a general hardness of 1–15 dGH. A moderate water flow is preferred.
Is Bucktooth Tetra (Exodon) peaceful or aggressive?+
Bucktooth Tetra (Exodon) is classified as highly aggressive with an aggression score of 9 out of 10. Careful tankmate selection is essential to avoid conflict.
How many Bucktooth Tetra (Exodon) should be kept together?+
Bucktooth Tetra (Exodon) is a schooling species and should be kept in groups of at least 12. Larger groups help distribute aggression and encourage natural schooling behaviour.
Does Bucktooth Tetra (Exodon) have any special tank requirements?+
Yes. Bucktooth Tetra (Exodon) benefits from driftwood (digestion/hiding) in the aquarium. These features help replicate their natural habitat and promote overall health and well-being.
Does Bucktooth Tetra (Exodon) need a lid on the tank?+
Yes. Bucktooth Tetra (Exodon) is a known jumper, and a tight-fitting lid or cover is essential to prevent escape. Even a small gap can be enough for a determined fish to leap out.

Similar Species

Ember Tetra

Hyphessobrycon amandae

Characins
2 cm Peaceful

The Ember Tetra is a striking, fiery orange-red nano fish native to the Araguaia River basin in Brazil. Extremely peaceful and active, they are perfect for planted and blackwater aquariums. They are tight schoolers and must be kept in groups to feel secure and display their best colors.

Congo Tetra

Phenacogrammus interruptus

Characins
8.5 cm Peaceful

A stunning, large schooling fish native to the Congo River basin. Known for their iridescent rainbow colors and active swimming behavior. Despite their size, they are notoriously peaceful and can be skittish, requiring ample swimming space, dim lighting or floating plants, and peaceful tank mates. Avoid keeping with fin-nippers.

Pictus Catfish

Pimelodus pictus

Catfish
12 cm Mostly Peaceful

An extremely active, striking silver catfish with black spots and incredibly long barbels, native to South America. While peaceful toward similarly sized tank mates, they are highly effective nocturnal predators that will easily swallow small fish (like Neon Tetras) whole. They are scaleless and possess sharp pectoral spines that can easily become entangled in aquarium nets.

Rummy-Nose Tetra

Hemigrammus rhodostomus

Characins
5 cm Peaceful

Renowned as the tightest schooling fish in the freshwater hobby. They feature a bright red nose, a silver body, and a black-and-white checkered tail. They are excellent 'indicator fish'; their red noses will fade to pale pink if water quality drops or the fish are stressed. While there are three very similar species (H. rhodostomus, H. bleheri, P. georgiae) often sold under the same name, their care requirements are identical.

Forktail Blue-eye

Pseudomugil furcatus

Rainbowfish
5 cm Peaceful

A highly active, nano shoaling fish native to Papua New Guinea. Recognized by their striking blue eyes and energetic swimming patterns. They are peaceful but require open horizontal swimming space and the company of their own kind to thrive. Due to their short lifespan (2-3 years), they mature quickly and display near-constant courtship behavior.

Neon Tetra

Paracheirodon innesi

Characins
4 cm Peaceful

One of the most iconic freshwater fish in the hobby, famous for its striking iridescent blue and red stripes. Originally from the blackwater streams of the Amazon basin, they prefer slightly cooler water than many tropical fish and must be kept in schools to thrive, display natural behaviors, and feel secure.