Bucktooth Tetra
Exodon paradoxus
The Bucktooth Tetra (Exodon paradoxus) is an aggressive fish that's best left to experienced keepers. Give it a tank of at least 170 litres (45 US gallons), water held at 73-82°F, and a pH of 5.5-7.5. Always keep a group of at least 6 - they feel safest in numbers.
Captive lifespan reflects typical experience in a home aquarium, not maximum recorded age; genetics, sourcing, and care vary.
Natural distribution
Mostly South America
- South America
Regional colours match the stocking calculator's origin map.
Bucktooth Tetra Tank Setup
Give them a tank of at least 170 litres (45 US gallons). As open-water swimmers they care more about swimming length than height, so a longer tank is ideal. Keep the water at 73-82°F with a pH around 5.5-7.5, and avoid sudden swings. Always keep a group of at least 6 of their own kind - kept alone or in pairs they tend to turn shy, nippy, or wash out in colour. They reach about 12 cm as adults, so don't be misled by the small juveniles sold in stores.
What Do Bucktooth Tetras Eat?
They have small mouths, so stick to small foods: crushed flake, fine granules, and now and then a treat of frozen or live foods such as daphnia or baby brine shrimp. Anything too large simply gets ignored.
Bucktooth Tetra Tank Mates
A scale-eater. Keep in a species-only tank of at least 12 - smaller groups turn on each other - and never with slow or long-finned fish. The Bucktooth Tetra is aggressive, which is the first thing to weigh up when you choose tank mates. It's a known fin-nipper, so avoid bettas, guppies, and other slow, long-finned fish. It's predatory, so anything small enough to fit in its mouth will be treated as food rather than a companion. It's a shoaling fish, so settle a group of 6 or more of its own kind before adding anything else - a stressed, lonely fish is far more likely to nip or hide. Before you buy, run your full stocking list through our stocking calculator. It weighs temperament, adult size, and water needs together, which a single species page can't do on its own.
Are Bucktooth Tetras Good for Beginners?
Not a sensible first purchase. Get the tank cycled, keep easier fish stable for a year, then revisit if you still want the extra work this species demands.
Bucktooth Tetra - frequently asked questions
What size tank do Bucktooth Tetras need?
Bucktooth Tetras need a tank of at least 170 litres (45 US gallons). A bigger tank is always easier to keep stable, and gives them more room to settle in and behave naturally.
How many Bucktooth Tetras should I keep together?
Keep a group of at least 6. Bucktooth Tetras are a shoaling species and become stressed, lose their colour, or hide when kept singly or in pairs.
What water parameters do Bucktooth Tetras need?
Keep them at 73-82°F with a pH of 5.5-7.5, steady rather than chased to an exact figure. In a cycled tank, ammonia and nitrite should both read 0 ppm, with nitrate kept low through regular water changes.
What do Bucktooth Tetras eat?
Bucktooth Tetras have small mouths, so they need small foods. Crushed flake and fine granules form the staple, with the occasional treat of frozen or live foods such as daphnia or baby brine shrimp. Feed small amounts once or twice a day, and remove anything they don't eat.
Are Bucktooth Tetras good for beginners?
Bucktooth Tetras are not a beginner species. They need precise conditions and consistent maintenance, so build experience with hardier fish before keeping them.
Common mistakes with Bucktooth Tetras
- Buying fewer than 6 - Bucktooth Tetras need a proper school to feel secure; isolated individuals hide, fail to colour up, or become stressed.
- Underestimating tank size - the minimum footprint is 170 litres (45 US gallons); impulse buying into a smaller tank leads to stress and shortened lifespan.
- Mixing with long-finned fish - Bucktooth Tetras will nip at bettas, angelfish, and other fish with flowing fins, causing stress and infection risk.
Building a community? Run the full list through the stocking calculator before you add anything else.
Great tank mates
Chosen from temperament, overlapping temperature/pH bands, plausible minimum tank footprints, and size versus yours in App-aquatic data. Hobby nuance always wins - verify stocking and temperament before purchasing.
Check Bucktooth Tetra against any other fish → Compares water parameters, predation risk, fin nipping and tank size, and draws both at life size.
Fish to avoid mixing with Bucktooth Tetras
These well-known species are commonly sold alongside this fish but are not recommended tank mates - verify before purchasing.
- OscarPredator - Oscar will eat or injure smaller tank mates
- Neon TetraIncompatible temperament or care requirements
- Panda CoryIncompatible temperament or care requirements
