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The bucktooth tetra is an interesting and unique freshwater fish that can be a showstopping addition to any aquarium.
However, these humorously-named fish can be a bit hard to own due to their aggressive temperament and scale-eating antics (yep, you read that right!), making them one of the worst fish to house in a community tank.
If you’re thinking of raising bucktooth tetras, here’s everything you need to know about their care, including diet, tankmates, aquarium parameters, breeding, and more.
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
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 on 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 a 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.
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 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.
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 55-gallon 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.
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. I’ve written an in-depth guide on the best 55-gallon aquarium heaters if you need help selecting one!
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 it 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 types of plants as despite the species’ scale-feeding antics, they will not damage plants.
Fine-leaved plants, grass-like plants, and 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 with 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, 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, and fish (including the scales!), and other meaty fare 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, bloodworms, 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.
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!
If you’re after more advice on tetra-like fish and other species, check out my other fish care guides, such as this guide on how to take care of neon tetra fry and how many neon tetras in a 10 gallon tank. Or see friendly tetra varieties such as the diamond tetra, emperor tetra, lemon tetra, or silvertip tetra.
- 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