Bucktooth Tetra (Exodon Paradoxus) Ultimate Care Guide

Anyone who has been keeping fish for more than 5 minutes knows Tetras are friendly, peaceful fish that fit well into a community setup. Well, it might surprise you to learn, not all Tetras are calm and friendly, and laid back. Meet the Bucktooth Tetra.

I have been keeping the fascinating Bucktooth Tetra for a number of years now and they truly are a unique species of fish. Bucktooth Tetras are often described as ‘an aggressive shoaling fish that will attack any small tankmates’. In my experience, that is a pretty fair description!

Bucktooth Tetra Characteristics

Common Name:Bucktooth Tetra
Scientific Name:Exodon paradoxus
Family:Characidae
Origin:Brazilian Amazon
Tank Distribution:All areas
Adult Size:6” (15cm)
Life Expectancy:7-10 years
Care Level:Moderate
Minimum Tank Size:40-Gallons (180 Litres)
Breeding Method:Egg scatterer
Temperature:73°F to 82°F (23°C – 28°C)
pH:5.6 – 7.6
Hardness:0-20°H


Bucktooth Tetra Origins

The Bucktooth Tetra can be found in rivers and streams throughout the Brazilian Amazon and the Tocantins River basins. There are also reports that the Bucktooth Tetra can be found in Rio Branco, Guyana many miles north of Brazil.

Map of Bucktooth Tetra Range, Central South America

Bucktooth Tetra Habitat

Many accounts of the Bucktooth Tetras habitat, describe the regions as being ‘savannah-like grasslands’. These open areas with few trees mean clear waters with little to no overhanging vegetation.

What Size Aquarium For Bucktooth Tetra?

The Bucktooth Tetra needs some space to swim. It is a shoaling fish (not to be confused with a schooling fish. More information on schooling vs shoaling in this article I wrote ) and as such likes to swim around.

I keep my Bucktooth Tetras in a 4’ (120cm) long aquarium and they seem more than happy. If you keep Bucktooth Tetras in an aquarium that is too small, you may well find they turn on one another and you end up with just a couple of survivors.



How Should A Bucktooth Tetra Aquarium Be Set Up?

Bucktooth Tetras look at their best when kept in a heavily planted tank. In my Bucktooth Tetra setup, I have a sandy substrate with lots of plants and a few pieces of bogwood along with some roots dotted around. The plants not only look natural and help absorb some of the fish waste, they also provide refuge if one or more of the tetras needs respite from the pack.

I have a good light over my Bucktooth Tetra aquarium to keep the plants growing. The bright light makes the colors on the Bucktooth Tetras really pop!

Filtration is very important in a Bucktooth Tetra setup. As these fish need to be kept in large groups, they produce a lot of waste and the filter needs to be able to process that waste quickly. I use a Fluval 407 on my Bucktooth Tetra aquarium (more information in my article here titled ‘Are Fluval Filters Any Good?’)

Bucktooth Tetras do require their water parameters to be good, so I carry out a 30% water change each week too, just to keep my Bucktooth Tetras in good shape.

Bucktooth Tetra Behavior In The Aquarium

Do not be fooled by the word ‘Tetra’ in the Bucktooth Tetras name. These fish are not for the community aquarium.

Bucktooth Tetras are vicious. They will attack any smaller tank mates, especially any other fish which are silvery in color. Bucktooth Tetras will quickly strip the fins and scales off any fish in their aquarium. I have even seen them attack fish much larger than themselves. Think of the Hollywood version of a piranha attack, and you won’t be far off!

Bucktooth Tetras are best kept in a species-only aquarium. The only fish I have in with my Bucktooth Tetras is a large Bristlenose Pleco. My Bucktooth Tetras don’t pay him any attention. I can only imagine it is because he is black and not ‘shiny’.

Bucktooth Tetras need to be kept in a pack. The larger the number of fish you have, the less likely they are to pick on an individual member of their own group. I would advise keeping a minimum of a dozen Bucktooth Tetras together, but aim to keep as many as you can squeeze into your aquarium. 20 is better than 12, 30 is better than 20 etc.



What Do Bucktooth Tetras Eat?

Research into wild Bucktooth Tetras has shown they eat a lot of insects and scales from other fish. In captivity, they readily accept bloodworms, prawns, and small sections of dead fish.

I have successfully transitioned mine onto commercially available foods. I often feed them Vibra Bites (which do look a lot like bloodworms) and floating pellets.

Mealworms and small crickets make a fine addition to your Bucktooth Tetras diest as would live mosquito larvae.

Breeding Bucktooth Tetras In Captivity

Bucktooth Tetras have been bred in captivity. Reports suggest a breeding setup comprising a 20-gallon aquarium with either a large clump of java moss or a false bottom works best.

The female Bucktooth Tetras will scatter the eggs and the males will fertilize them as they fall through the water. Reports suggest Bucktooth Tetras will happily eat their own eggs, so the adults should be removed once spawning is complete.

The eggs will hatch after two or three days. There appears to be very little data on raising the fry, but there is a high probability that cannibalism will take place, so the fry should be kept well fed at all times.



In Conclusion

Bucktooth Tetras are a truly fascinating species of fish to keep in captivity. Their coloration is stunning and they look amazing against the bright greens of a planted aquarium. Keeping such an aggressive species is a real challenge and one which I have found really enjoyable.


About the Author

I’ve been keeping, breeding, and showing tropical fish for nearly 30 years. Over that time I’ve done it all! I’ve had great success and I’ve made some really foolish mistakes (like the time I bought an Asain Walking Catfish). Read more…
Richard James
Editor