Bucktooth Tetra – Species Profile & Facts

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Many fish keepers out there look forward to add a Bucktooth Tetra to their fish collection. If you are one of them, make sure to read our informative guide about this species. Getting to know your next fish is an essential first step toward proper care.

What makes the Bucktooth Tetra (Exodon Paradoxus) special is that its body is covered by two black and some red patches over its green, yellow and silver scales. One of the black spots is below the dorsal fin while the other one is always next to the tail. Besides that, it has a typical oval body shape sized around 3 inches. Now to make things clear right at the beginning, this is a quite tricky fish to keep.

Sometimes, they can be even more aggressive than Piranhas. Although their name suggests otherwise, they don’t even have teeth. But this still doesn’t prevent them from damaging the scales of other species. Therefore, it is recommended to keep only Bucktooth Tetras in your aquarium, otherwise things can become rather chaotic.

They can cause a lot of stress if kept around other fish species to the point of making them ill. It usually doesn’t matter if the other fish is bigger, smaller or of equal size. Without further ado, let’s see what else you need to know about this species!

Bucktooth Tetra Natural Habitat

Out in the wild, the Bucktooth Tetra lives in the river basins of the Amazon and Tocantins. Both of these can be found in South America. The scientific name for this species is Exodus Paradoxus. It is good to know in case you can’t find them as Bucktooth Tetras since people who deal with fish know this in every language.

They have developed their hectic and predatory lifestyle in those rivers. Back in 1932 is when they became popular in the aquarium trade. Their appearance is typical to tetras which all have similar oval shaped bodies. In the Amazon and Tocantins, they eat invertebrates, some plants and other fish around them as well.

Whether the other fish is bigger or smaller, it doesn’t matter. If it’s smaller then they eat it. If it’s bigger, then they eat their fins only. Either way, they show no mercy toward other fish species. The life expectancy of a Bucktooth Tetra is around ten years.

Bucktooth Tetra Fish Tank Requirements

The Bucktooth Tetra, by its nature, loves to be around as many plants as possible. It not only makes the water well-oxygenated but also provides plenty of hiding places for your fish. They don’t always like to be social and sometimes they are stressed out as well.

That is when they start looking for places to hide and there isn’t anything more straightforward than to use disappear among all that greenery. Thanks to these plants, there is not as much additional water filtration required.

This species doesn’t particularly like floating plants so it is better to buy other types. They can be also complemented with driftwood pieces to make the whole picture more decorative.

Of course, rocks, pots and artificial caves are not out of the question either. You should buy an aquarium that is between 30 and 60 gallons of size depending on how many of them you want to keep. Long and wide fish tanks are preferred because Bucktooth Tetras are very active and they need free space to swim around.

Bucktooth Tetra Water Conditions

You can hardly find a fish that is not sensitive to water conditions. The Bucktooth Tetra is no exception. Therefore, you should aim to keep the temperature somewhere between 73- and 82-degrees Fahrenheit. The acidity should be between 5.5 and 7.5 pH while the water should be kept rather soft, between 5 and 20 pH.

The more of these fish you keep, the better water filtration is required. The amount of waste generated by them has to be dealt with. If you are not careful, the water conditions can get worse and it will cause your Bucktooth Tetras to fight with each other.

When it comes to their health, this species is rather hardy so you shouldn’t worry about them getting any particular disease. As long as the water is clean and you feed them a healthy diet, they are going to thrive.

Bucktooth Tetra Diet & Feeding Schedule

Since Bucktooth Tetras are rather carnivores, they live on insects out in the wild. They are also not going to deny other fish’s scales if they can chip away some. However, this doesn’t mean that you should keep them on such a strict diet at home.

Instead of giving them live food, you can also feed them with mussels, krill, earthworms, and lancefish. Furthermore, dried foods such as pellets and flakes from the pet shop are also acceptable. The rule of thumb is to feed them meaty foods most of the time.

It is important to keep in mind that Bucktooth Tetras are vicious predators by their nature. They are more than happy to eat the insects you can find around the house. Those are the ideal treats for them. Now if you keep this species has tank mates, then it is going to steal food for them whenever possible.

Therefore, you should pay particular attention whether your other fish are properly fed. You can feed the Bucktooth Tetra several times each day by giving it small amounts.

Bucktooth Tetra Tank Mates

As we have mentioned above, you basically have no option than to set up a single species aquarium. Other fish simply can’t live around them without getting injured and totally stressed out. Simply put, Bucktooth Tetras are aggressive predators. If you put another species in the tank, it is going to become a warzone.

If you keep them with their own kind, however, then they are going to be calm and peaceful. This is especially true if you keep them in large schools. They will swim together in a manner that is going to be delightful to watch. You will immediately forget their inherently aggressive nature.

Keeping a smaller school of Bucktooth Tetras, on the other hand, is very risky. If the school is too small, they are going to attack each other viciously. The fight will last until only one fish remains. In our opinion, it is not worth the risk so you should definitely aim to buy them in larger numbers.

A school of 20 to 25 Bucktooth Tetras is a desirable number. This will guarantee that they are going to strive together in peace. Make sure there is at least a dozen of them in the same tank.

If one or more of them get sick, then they are eventually going to be attacked by the others. They are going to spot the weaker members of the group and there will be no mercy. If you spot that one of them is not feeling well, then what you can do is to put him in a separate aquarium until he gets better.

Bucktooth Tetra Breeding

Bucktooth Tetra breeding is definitely not something we can recommend for beginners. It is uncommon even among the most experienced fish keepers. Keeping a female and a male in the same tank is already quite problematic. There is a high chance that they are going to fight with each other instead of mating.

On top of that, you simply won’t be able to tell which one is the male and which one is the female. There are no differences between their appearance. Your only option is to keep a large school of Bucktooth Tetras, males and females as well. If you are patient, it is going to happen eventually.

But then again, you need to be prepared to remove the eggs as quickly as possible. Otherwise, the parents are going to eat them and your plan is going to be ruined. This problem can be solved by carefully setting up the aquarium so that there are deep and narrow spots.

The females prefer to lay their eggs there and then it is going to be hard for the parents to reach and eat them. The Bucktooth Tetra tends to eat its own eggs and its own fry as well. The fry simply can’t live together with the adults so you will have to remove them.

With proper care, you will be able to raise them in a separate fish tank.


The Bucktooth Tetra is only recommended for those fish keepers who like aggressive fish. This is a unique and decorate species that is going to live a peaceful life if kept in a single species aquarium. The best thing about them is that they require a smaller aquarium compared to Piranhas or cichlids.

They allow you to still own a school of vicious predators that are out for the hunt. As long as you keep a large group of them, you are barely going to have any problems. We hope this article is going to encourage you to set up an aquarium for these little predators and enjoy their uniqueness.

Bucktooth Tetra Image: Flickr

Author Image Fabian
I’m Fabian, aquarium fish breeder and founder of this website. I’ve been keeping fish, since I was a kid. On this blog, I share a lot of information about the aquarium hobby and various fish species that I like. Please leave a comment if you have any question.
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