Bucktooth Tetra Complete Care Guide: Everything You Need To Know

Dr. Mollie Newton
Published by Dr. Mollie Newton PHD| Senior Editor
Last updated: April 6, 2024
Review Process and Evaluation Criteria
We conduct hands-on testing for all the products highlighted in our reviews and guides. Through anonymous product ordering and involving an independent team of testers, we gather direct experience to offer recommendations backed by data.

The bucktooth tetra is a unique and fascinating freshwater fish that could be the main attraction in any aquarium. However, despite their humorous name, these fish can be quite difficult to look after due to their aggressive tendencies and habit of eating scales (yes, you read that right!). Their behavior ultimately makes them one of the least suitable species for a community tank. If you’re contemplating the notion of raising bucktooth tetras, this comprehensive guide covers everything you need to know about their care, encompassing diet, suitable tankmates, proper aquarium conditions, breeding, and more.

Article Summary

  • Bucktooth Tetras are native to South America, including the Amazon River Basin.
  • They enjoy a well-lit aquarium with plants and dark substrate; fine-leaved plants, grass-like plants, broad-leaved species, and floating plants work well in their tanks.
  • Bucktooth Tetras are carnivores and will eat a variety of meaty foods, including live, frozen, and dried options.

Origin, Habitat, and Distribution

The bucktooth tetra (Exodon Paradoxus) is a freshwater fish that is a member of the characin family.

It’s found naturally in South America, including Guyuna, the Amazon River Basin, and Tocantins River Basins.

Unlike most other tetra species, the bucktoothed tetra is boisterous, aggressive, and a fierce hunter.

Main Food Source

In fact, one of their main food sources is fish scales!

Although not as popular as some other tetras, such as the diamond tetra and the silvertip tetra, the bucktoothed tetra is readily available in the aquarium trade. Their stunning coloration and bold temperaments make them a sought-after fish by many aquarists.

Characteristics and Appearance

Exodon paradoxus2 by Clinton and Charles Robertson(1)

Like other types of tetra, bucktooth tetra is a relatively small fish, torpedo-shaped, and vibrant in color.

They have a stunning metallic silver body that displays flecks of yellow, green, and red. There are two large black patches on their body, one in the middle and another at the base of their tail.

The fish’s fins are transparent with a touch of yellow. Bright red and orange splotches also adorn their dorsal fin, as well as their pectoral and anal fins.


Despite what their name suggests, the bucktooth tetra’s actual teeth are not protruding teeth! They have powerful jaws and serrated lips, allowing them to easily rip out the scales on other fish.

Furthermore, the fish’s teeth and lips are in an outward-facing position, increasing their biting ability.


As mentioned earlier, bucktooth tetras have a silver base color with hints of yellow, red, and green.

They have yellow fins with red and orange tips, as well as two large black spots on their body.

In bright lighting, the metallic color of the bucktooth tetra can shine a beautiful blue and purple iridescence.


Bucktooth tetras are fairly hard fish and have longer lifespans than some other species of tetra, averaging up to 10 years with good care.


The bucktooth tetra usually reaches between 4 to 5 inches in length in the home aquarium, but in the wild, they can grow up to 6 inches in length!

Behavior & Temperament

Bucktoothed tetras have a boisterous and aggressive temperament, especially towards other fishes with silvery or shiny coloration. They will quickly tear off the fins and scales of fish they deem prey, which is why they can be difficult to house in a community tank.

This fish usually occupies the middle of the water column, but they will venture out to both the top and bottom during feeding time or if another tankmate piques their interest.


Bucktooth tetras are shoaling fish, so It’s best to keep them in large groups of at least 12, ideally as many as you can fit into your tank. When housed in only a pair or small groups, these tetras will often target and bully each other until you’re left with just one fish.

Keeping these aggressive fish in large groups will prevent cannibalistic and territorial behavior, helping ensure only weak or sick specimens get picked off. Besides, observing bucktooths in huge shoals is interesting as they are very energetic and interactive!


Purchase a group of bucktooth tetra at the same time as new residents are usually bullied or attacked by existing members of the shoal.

Sexual Difference

Unfortunately, it is difficult to tell the difference between male and female bucktooth tetras as they don’t display any sexual dimorphism. However, males tend to be more active than females.

How to Keep Bucktooth Tetras

bucktooth tetra Exodon paradoxus by Brian Gratwicke
Bucktooth tetra Exodon paradoxus(2)

Bucktooth tetras are fairly easy to keep as they are a hardy species, but their aggressive nature may be off-putting to beginner aquarists.

Additionally, these fish need a fairly large tank, especially as they do best when housed in large groups.

Tank Size

The right aquarium size for bucktooth tetras depends on how many you want to keep, but for a shoal consisting of 12 tetras, you should opt for at least a 55-gallon aquarium as they are an active species. Bigger is always better, so try to purchase the largest tank you can afford.

Make sure to also get a good aquarium stand as you don’t want your table breaking down on you! These tanks can get quite heavy.

If you’re planning on keeping your bucktooths with other fish, you’ll need to consider the size and needs of their tank mates, too!


Long and wide tanks are preferable for these species as they are energetic and require a lot of open swimming space.

Water Parameters

Bucktooth tetras don’t need complex water conditions to thrive other than optimum water quality. They will do well in water parameters of most other South American tropical fish species.


These fish originate from tropical waters, particularly in the Amazon River Basin, so they need warm water in their tank. Aim for between 72 to 82 degrees Fahrenheit, ideally around 75 degrees.

You can increase and maintain the water temperature of your tank using an aquarium heater. Depending on the aquarium size you’ll need around 2.5-5 watts per gallon, so for a 55-gallon tank you’ll need at least a 150 watt heater.

pH level

Bucktooth tetras prefer slightly acidic water with a pH level between 5.5 and 7.5. water hardness should be between 0 to 20 dH as they like soft water.


This species needs excellent filtration in order to thrive, so you’ll need a powerful filter to take care of the waste they produce.

The water should be well-oxygenated and have a medium current.

As bucktooth tetras need a fairly large tank, you’ll need to install a filter with an appropriate flow rate for the capacity of your aquarium. Select a filter that can turn over your water volume four times per hour.

For instance, a 55-gallon aquarium will need a filter with a flow rate of at least 220 GPH (gallons per hour).

What to Put In Their Tank


Now that you need a bit more about the care needs of the bucktooth tetra, let’s go over the ideal setup for this species.


The bucktooth tetra spends a large portion of time out in the open as they are extremely active, but they also enjoy a lot of plants in their aquarium. Good lighting will not only encourage growth in live plants but will also enhance the colors of your fish.

For most planted tanks, lights with an output of around 6500k are usually sufficient, but you may need a more powerful light depending on the lighting needs of your plants.


Any substrate will work just fine in a bucktooth tetra aquarium, including gravel, sand, dirt, or nutrient-rich substrates designed for live plants.

However, a dark substrate will complement the colors of this fish and make them appear more vibrant.


Bucktooths enjoy a lot of plants in their aquarium. Aquatic plants not only create a more natural habitat for your fish, but they also help aerate and filtrate your tank water.

You can use any type of plant as despite the species’ scale-feeding antics, they will not damage plants.


Fine-leaved plants, grass-like plants, broad-leaved species, and a few floating aquarium plants work great in buck toothed tetras tanks.

Some good plants for this fish include Amazon swords, java fern, and vallisneria species. Adding lucky bamboo in aquarium setups is also a good choice as they help better simulate the natural environment from which a lot of tropical fish originate.

Live plants accompanied by other decorations like artificial caves, driftwood, slate, and pots are sure to make your fish feel right at home!

Bucktooth Tetra Tank Mates

Bucktooth tetras are useless community fish due to their aggressiveness and tendency to eat scales.

They do best when housed in a separate tank with the same species.

Even though bucktooth tetras are not overly big in size, they are big eaters! A group will easily injure and kill a larger fish.

Once they’ve set their eyes on a target, a shoal of bucktooths will swarm and take down a fish in a matter of minutes.

Here’s an interesting video of bucktooth tetras feeding as a group…

Unfortunately, no fish is safe in an aquarium with bucktooths.

Some aquarists have successfully kept bucktooth tetras with bottom-dwelling scaleless species like loaches and plecos.

Personally, I wouldn’t advise this as you can’t guarantee that your tetras won’t eventually kill off your fish. Besides, the stress of living with bucktooths could be detrimental to the health of your other fish.

It’s much safer and beneficial to keep bucktooths in a species-only tank.


Fortunately, the bucktooth tetra is not prone to any species specific diseases. However, they can still develop illnesses and health issues that are common in other fishes like ich, fin rot, fungal infections, bacterial infections, and flukes, among others.

Bucktooth Tetra Feeding

The bucktooth tetra is a carnivore and not a picky eater by any means, feasting on a variety of meaty foods in the wild.

Their diet consists of small insects, shrimp, fish (including the scales!), and other meaty fares they can get their fins on.

In captivity, these tetras will readily accept live, frozen, and dried foods. 

You can feed them mussels, chopped prawn, live blood worms, earthworms, mysid shrimp, brine shrimp, krill, live feeder fish (and dead alternatives), and pellet or flake food designed for carnivorous fish.


Give them a range of foods to ensure they get plenty of nutrients. These fish are greedy feeders, so you won’t have a quiet tank unless you feed them enough food every day. Offer your fish food 2 to 3 times a day – as much as they can eat in 2 to 5 minutes.


Breeding the bucktooth tetra is extremely difficult, but that doesn’t mean it’s impossible.

These fish don’t make the best parents (they will likely eat their young), so you should set up a separate breeding tank with similar water parameters to your main bucktooth tetra tank.

Bucktooth tetras are egg layers, so after they successfully lay eggs, the female will scatter her eggs in the tank to then be fertilized by the male.

Put some fine-leaf plants in the tank to help protect the eggs from the adults.


You could also place a layer of mesh at the base of the tank, allowing the eggs to fall through to keep them safe from the adults. Feed your adult fish a high-protein diet a few days before moving them into a breeding tank.


To trigger spawning, change 50% of the water and replace it with water that is a few degrees hotter as this will replicate the changes in temperature that occur during the breeding season.

As soon as you spot eggs in the breeding tank, remove the adults.

The eggs will hatch in a few days. When the fry are free-swimming, feed them baby brine shrimp.

Unfortunately, it’s likely you will lose some of the fry, especially as even baby bucktooths display cannibalistic behavior.


Your best bet is to keep the fry well-fed to decrease the likelihood of them turning on one another.

Final Thoughts

I hope I helped you learn more about the unique bucktooth tetra and their care needs so you can raise happy, healthy fish.

Be sure to share this post so your friends and other aquarists can increase their knowledge of this ultra aggressive species!

Image References

  • Featured Image – Armbruster, J. (2011, November 19). DSCN6064 [Photo]. Wikimedia Commons. https://commons.wikimedia.org/wiki/File:DSCN6064_(6260740474).jpg#/media/File:DSCN6064_(6260740474).jpg
  • 1. Clinton & Charles, R. (2021, August 10). Exodon paradoxus [Photo]. Exodon Paradoxus. https://upload.wikimedia.org/wikipedia/commons/0/03/Exodon_paradoxus2.jpg
  • 2. Gratwicke, B. (2008, November 8). bucktooth tetra Exodon paradoxus [Photo]. Flickr. https://www.flickr.com/photos/briangratwicke/3067059860
You May Also Like