Bucktooth Tetra [Care Guide] – Size, Tank Mates, Diet & More

The bucktooth tetra is an active and unique fish that stands out from other freshwater fish. Find out more in our extensive care guide.

Bucktooth Tetra – Quick Facts

In a rush? Check out the quick facts about Bucktooth Tetra below.

Fish Info

Scientific NameExodon paradoxus
Common NamesBucktooth tetra
AppearanceLight tan, two black spots, bright red dorsal fin.
DifficultyBucktooth tetras are not difficult to care for if their environment is kept stable.
DistributionThe bucktooth tetra is found naturally in South America. It is found in Guyana, the Amazon River Basin, and the Tocantins River Basin.
LifespanAround 10 years
TemperamentThe bucktooth tetra is a predatory and aggressive fish.
Keep in Groups of12+
Tank MatesThe best tank mates for bucktooth tetra are other bucktooth tetras.
DietThe bucktooth tetra diet consists of various foods, such as shrimp, bloodworms, earthworms, fish fillet, flake and pellet foods.
Length12-15 cm
Sexual DimorphismMales are usually slightly thinner than females and the males also have slightly longer anal and dorsal fin rays.
Breeding DifficultyBreeding bucktooth tetra is difficult because they are egg-layers that don’t have parental instinct and will eat their eggs.

Water/Tank Recommendations

Water TypeFreshwater fish
Water Temperature72–82-degree Fahrenheit / 22–28-degree Celsius
Water pH5.5 to 7.5
Water HardnessThe ideal water hardness for bucktooth tetra is 0-20 GH.
Tank size30 to 60 gallons


Bucktooth tetras are unique freshwater fish that many aquarists don’t know about. They’re not very popular, which means you probably won’t see them in big stores or on display at conventions.

But we think they should be!

These fish have an interesting look and behavior pattern that makes them fun to watch. Plus, caring for them is quite easy! These are great beginner-friendly tropical fish with potential for success in pretty much any tank setup.

In this guide, you’ll learn everything there is to know about bucktooth tetra care. Everything from their size and lifespan to ideal tank mates and diet!

About Bucktooth Tetra

The bucktooth tetra is a unique freshwater fish that’s not as common as other species. Their interesting appearance and playful behavior make them quite appealing to aquarists who are looking for something different!

The scientific name of the Bucktooth Tetra is Exodon paradoxus. The origin of their genus, Exodon, comes from the Greek words ekso (outside) and odontos (teeth). This was given to them due to their outward-pointing canines!

These fish were first discovered in 1844 by Müller & Troschel. They aren’t widespread among the aquarium community yet but continue to gain popularity with collectors worldwide.


Bucktooth tetras are small, light tan-colored fish with a red dorsal fin. Like other types of tetra species, they have thin bodies and long tails that help them to navigate currents in the wild. They have two distinct black spots on them, one in the center of their body and one near their tale.

NOTE: These fish are wonderful to look at and should be a welcome addition to your community tank!

Their Length

The average length of a bucktooth tetra is around 12 to 15 centimeters long. These are obviously not very big fish, but for tetras, they’re smaller compared to other types within the family.

As they are small, they can be kept in smaller tanks as well. While it’s recommended that you keep these fish in large groups, a single bucktooth tetra is not going to take up too much space.


The typical lifespan of a Bucktooth Tetra is around ten years.

The quality and level of care they receive will affect the length of time they live. As you can assume, fish kept in subpar living conditions are much more likely to experience health problems and die early.

Some fish will even die within a few months of being put into an unsuitable tank. So please do keep an eye on your fish and provide the best care you can.

Sexual Dimorphism

Males are usually slightly thinner than females and the males also have slightly longer anal and dorsal fin rays.

Females are usually a bit larger than their male counterparts.


The ideal habitat for bucktooth tetras is a natural freshwater environment with plenty of hiding places.

Bucktooth tetras tend to feel more comfortable in shallow waters. In the wild, these fish are found in rivers and streams where there isn’t too much depth. They need things like plants and driftwood to hide in from predators when they are feeling threatened (this applies even if they have no other animals sharing their tank).

When it comes to substrate material, a sandy riverbed type mix works best for bucktooth tetra because it mimics their natural environment as well as provides great water flow through the sand.

Caring for Bucktooth Tetra

The bucktooth tetra is an easy fish to care for. They’re not difficult to feed, do well in most freshwater tanks, and adapt well to a good range of water temperatures.

There are things you need to watch out for. These predatory freshwater fish have the potential to become aggressive if they are kept with other species of their size (or smaller).

In general, the bucktooth tetra is a hardy fish that can be kept with other similarly sized freshwater fish. Don’t expect these to act like more peaceful bottom-feeder species though!


The bucktooth tetra is an opportunistic predator. They will eat anything they can find in the wild, which includes insects and smaller fish. They are known to behave a little like piranhas, eating away at their prey.

In captivity, it’s best to feed them a balanced diet of frozen or live food. Brine shrimp are their favorite! Bucktooth tetras also like bloodworms, earthworms, and chopped-up pieces of fish. You can also provide pellets if you want to be sure that your fish get enough protein from their diet (this isn’t needed, though).

NOTE: Some owners have had success feeding their bucktooth tetras frozen foods while supplementing with live food every once in a while. This will give your fish some variety and provide them with the maximum amount of vitamins.

How Often & How Much to Feed Them

Bucktooth tetras should be fed every few hours, so multiple times a day.

These fish will often eat until they’re full. Therefore, it’s important to keep a watchful eye on how much food is being consumed during each feeding session. If your bucktooth tetra doesn’t eat all of its food at once, don’t go overboard with the quantity next time (make sure there is enough).

Feeding too much can lead to health problems.

Possible Diseases

Bucktooth tetras are prone to the usual freshwater fish diseases. These include ich, fin rot, and other bacterial infections.

Ich is a most common disease problem that affects all kinds of freshwater fish. It’s caused by a highly contagious parasite called Ichthyophthirius multifiliis. Typically found on weak or stressed fish, it can live for up to 28 days in water at room temperature without a host!

This means you must quarantine your sick fish if they become ill with this problem (or any other). Also, be vigilant about maintaining good water conditions so that your healthy fish do not fall prey to stress-related illnesses.

Tank Setup

The best way to set up a tank for bucktooth tetras is by matching their natural habitat as much as possible.

A substrate like sand is recommended because these fish will spend time digging in search of food and shelter. A sandy substrate also helps keep things tidy since these fish aren’t afraid of moving through your aquarium and stirring everything up!

Bucktooth tetras need plenty of hiding places. Plants like hornwort, java moss, and Anubias work very well for this purpose (as long as you don’t have aggressive bottom-feeders!). However, live plants require maintenance if you want them to thrive.

NOTE: It might be worth going with artificial plants if you notice significant uprooting or tearing of leaves (this indicates that there are too many diggers).

Aquarium Size

The minimum tank size for a group of bucktooth tetras is 30 gallons. A larger aquarium is recommended (60+ gallons), as this species belongs to the shoaling category and needs to be kept in groups.

NOTE: A good rule of thumb when it comes to choosing an aquarium size is that you should plan on adding at least two gallons of water per fish and more if possible (in other words, if you have 15 bucktooth tetras, get a 30+ gallon tank).

Water Conditions

The best way to keep the water conditions in your tank good for your fish is by mimicking their natural habitat as closely as possible. In their native environment, bucktooth tetras live in slow-moving waters with dense vegetation.

When setting up a tank for this species, you need to make sure there are ample hiding spots throughout the aquarium so that they have safe spaces where they can go to feel comfortable. This doesn’t mean you need tons of plants (although it does help), but rather occasional pieces of driftwood or large rocks for them to use if needed.


The ideal water pH for bucktooth tetra is between 5.5 and 7.5.

If your tap water has a very high or low pH, you’ll need to condition it before introducing it into the aquarium (this applies to all fish species).


The ideal temperature range for bucktooth tetras is between 72 and 82 degrees Fahrenheit, which is a very manageable level of warmth. Make sure to keep your thermometer handy when doing water changes or checking the overall health of your fish.


The ideal water hardness for bucktooth tetras is 0–20 GH. They aren’t very picky about hardness levels.

If you don’t have a water hardness meter, it might be a good idea to buy one so you can keep an eye on it.


A good external filter is essential, as bucktooth tetras tend to produce a lot of waste. A canister or hang-on-back model works best for tanks 30 gallons and up.

Test your water regularly for ammonia and nitrate levels to ensure they stay low.

Aquarium Plants

Plants are an essential part of a bucktooth tetra’s habitat. Not only do they make the tank more aesthetically pleasing, but plants can help with water quality as well.

Aquarium plants act as a natural filtration system, removing waste and toxins from the water so your fish don’t have to worry about illness or stress that comes along with poor water quality.

When choosing which plant species you want in your aquarium, consider keeping slow-growing aquatic varieties that won’t overtake the tank. Bucktooth tetras prefer live plants (such as hornwort) over plastic replicas because they provide shelter and comfort for these fish.

Behavior and Compatibility

Bucktooth tetras are highly active fish that usually swims around the upper half of the aquarium. However, they can dart to the bottom of the tank if startled or threatened by another fish in their group.

This behavior is quite common among predatory fishes, especially those that have large mouths.

The bucktooth tetra is a predatory and aggressive fish.

How Many to Keep Together

The number of bucktooth tetras that can be kept together is dependent on the tank size. A large group is better due to the fact that they are shoaling fish. We like to aim for 12+ in a group where possible.

If you have a very large tank with plenty of room to swim and hide, 15+ fish can live together without any problems.

A group of this size is recommended because it will allow the fish to swim and behave as a group. They are naturally social, so they need each other in order to feel comfortable within an aquarium setting.


Bucktooth tetras are predatory fish that will eat any small fish or invertebrate in the tank. They’re best kept with other bucktooth tetras, as they can become very territorial when alone.

When these types of aggressive fish inhabit a tank together, they form a pack to hunt and attack their prey! This behavior is why it’s so important to keep them away from other species.

Tank Mates

Due to their predatory nature and the tendency to feed on other fish, Bucktooth tetras are best kept as a single species, without any other species as tank mates.


Bucktooth tetras are egg-layers that don’t have parental instinct and will eat their eggs.

Because of this, breeding is a tricky process that requires some precautions. To start, you need to feed your fish plenty of live food so they have the nutrients needed for spawning.

Next, increase the water temperature by 1 degree every other day until it reaches 79 degrees Fahrenheit (about four days). Then slowly lower it back down to 74 degrees Fahrenheit over another three days. This simulates seasonal changes in the wild.

If done correctly, females should begin laying up to 500 eggs at once! Once she lays her batch of eggs on an available surface like plants or wood, remove them from the tank immediately for safety reasons – as mentioned above, bucktooth tetras do not display any parental instincts whatsoever.

Are Bucktooth Tetra Fish a Good Choice For Your Tank?

Bucktooth tetras are predatory and aggressive fish. They will eat any smaller fish or shrimp that you have in your tank, so it’s best to keep them alone with their own species only.

Overall, bucktooth tetras are beautiful and interesting fish that can add some color to your tank. However, their predatory behavior makes them an unsuitable choice for many aquarists.


If you’re looking for a fish with some flash, the bucktooth tetra might be just what you need. These fish are beautiful and have an interesting appearance that will add variety to your tank.

The bright red dorsal fin on this species is quite vibrant! It stands out against their light tan body color nicely and can offer a pop of color from across the room. You might even mistake it for another species at first glance!


Because these fish are predatory and aggressive, they require an appropriately large tank to ensure their safety. They will often target smaller fish in the aquarium.

Bucktooth tetras can be difficult to breed due to their lack of parental instinct.

Lastly, these fish are not recommended for beginners. They do best with experienced aquarists who know how to handle challenging situations.


Bucktooth tetras are fun and colorful fish that can add some interest to your freshwater tank. They’re quite active and will put on a show for you throughout the day!

If you have any questions about this species or suggestions on how we can improve our care guides, reach out to us directly.

We look forward to hearing from you!

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