What Are Tank Buster Fish? And 22 Tank Buster Species


Any dedicated fish keeper would want to give their fish the best living conditions possible. Each species of fish has specific requirements for housing size, water parameters, quantity and quality of food, etc.

Any fish species that grows too large to be kept in home aquariums is called a Tank buster. These fish need very large aquariums, eat a lot of food and make the aquarium water very dirty. Some species, like the Walking Catfish and the Giant Snakehead are invasive species in the USA.

How Big Does a Fish Need To Be To Be Called A Tankbuster?

Any fish that can potentially grow to more than 12 inches / 1 foot / 30.5 cms in length should not be kept in a home aquarium. If you have a species in mind that you would like to keep, you need to research its max adult size and other care requirements like feeding and water quality.

You can get a tank of a suitable size, if you know what size the fish will grow to. You can check out profiles for different fish species here.

Why You Shouldn’t Get a Tank Buster For Your Aquarium

1. You Probably Won’t Be Able To House or Care For Tank Busters Properly

Tank busters need massive aquariums to thrive. While some can get away with a 400 or 500 gallon tank, most will need a tank with several thousands of gallons of water. Not only do most people not have enough space for such huge tanks, they also need to be custom built and require substantial amounts of money.

Once filled with water, larger tanks are also extremely heavy, so they can only be placed at the ground floor of a building. The upper floors cannot withstand the enormous weight of these tanks, and can potentially cave in (yes, they are that heavy!).

Huge tanks require expensive equipment to run cleanly and efficiently, not to mention that your electricity bill will get bumped up quite a bit. Huge fish also eat huge amounts of food, usually meat, and are very expensive to feed.

Eating so much, they also poop a lot, which is why you need large and expensive filters. Routine cleaning and maintenance of larger tanks also takes a lot of time and effort.

2. Tank Busters Live Miserable Lives in Home Aquariums

Most people who have these fish keep them in large tanks, but they are still too small for the fish. This results in stunted growth for the fish. Also, since they have a massive bioload, the water in the tank gets dirty very quickly. Dirty water brings with it a host of problems. (read more about Bioload and its effects over here).

To try and avoid this, they are fed less food than they require, resulting in malnutrition. Due to these reasons, tank busters rarely ever reach their full lifespan. And even if they do, they lead stressful, miserable and unhealthy lives in the home aquarium.

3. You Won’t Be Able to Rehome Tank Busters Once They Grow Larger

Many of those that buy tank busters are aware that they will get too big. But they still buy them thinking that they will relocate 2the fish to a larger home once they get bigger. Don’t buy a fish with this in mind. When was the last time you saw someone with a tank large enough to hold tank busters? Such large tanks are very rare.

Even the public aquariums will probably not take in your fish, because of the health hazards it can bring with it. Remember, as with any animal, once you get a fish into your home, it is your responsibility to give it the best possible care.

4. Tank Busters Are Invasive Species

When tank busters get too big for the home tank and when their owners can’t find a place to rehome them, they just dump them into their local rivers or lakes. This can go either of two ways. Either the fish will die because of lack of food or unfavourable water/ temperature conditions, or it will adapt to the local conditions.

While you wouldn’t want it to die, you don’t want it to adapt either. It will eat the local fish / invertebrate species, and if a few more people dump in the same fish into the water, they can even begin breeding there. Their population will explode and cause the local ecosytem to get severely disrupted. This is another reason tank busters are best left alone.

This is exactly what happened with snakeheads in the USA. They breed in the rivers over there and eat the local species, so are now banned for sale as pets in many USA states.

These Are Commonly Available Tankbuster Species

  1. Common Goldfish
  2. Koi
  3. Tinfoil Barb
  4. Oscar
  5. Walking Catfish
  6. ID Shark
  7. Pangasius Catfish
  8. Red Tailed Catfish
  9. Tiger Shovelnose Catfish
  10. Ripsaw Catfish
  11. Plecostomus
  12. Arowana
  13. Giant Gourami
  14. Pacu
  15. Bala Shark
  16. High Fin Shark
  17. Alligator Gar
  18. Knifefish
  19. Giant Snakehead
  20. Peacock Bass
  21. Mbu Puffer
  22. Araipama

Disclaimer: The mentioned maximum size for each species is the size they usually get to. Being living creatures, some individuals may get even larger, so if you are getting some fish species for your pond, it’s best to assume that the fish may grow 4-5 inches longer than stated, and make arrangements accordingly. That way you won’t need to relocate the fish once it reaches mix size, even if it gets a little too big.

1. Common Goldfish

Scientific name: Carassius Auratus

Max adult size: 1.25 ft / 15 inches / 38 cms

Surprised to see the Goldfish on this list? The Common Goldfish, probably the most commonly kept aquarium fish in the world, can grow well past 1 ft / 12 inches in length. So it is advisable to avoid getting it for your tank. You could keep them in a large enough pond though. The other breeds of Goldfish stay a lot smaller, so those shouldn’t be a problem.

2. Koi

Scientific name: Cyprinus carpio

Max adult size: Depending on the variety, between 2 to 3 ft / 24 to 36 inches / 61 cms to 91.5 cms long

Koi are beautiful fish that are often sold at just a couple of inches in length.

Looking at them, it can be hard to imagine that they can grow to 3 ft in length. That’s longer than most beginners’ aquariums! They are best left alone. If you have a large enough pond, you can keep them there too.

3. Tinfoil Barb

Scientific name: Barbonymus schwanenfeldii

Max adult size: 1.25 ft / 15 inches / 38 cms

Not only are these too large for home aquariums, but they are also schooling fish, which means they need to be kept in groups of at least 4. If you like barbs, you can check out other species over here, as most other species are much smaller in size.

4. Oscar (and other large Cichlids)

Scientific name: Astronotus ocellatus

Max adult size: 1.25 ft / 15 inches / 38 cms

Yes, although not usually thought of as tankbusters, Oscars do get too large for most home aquariums. There are quite a few cichlids that get over 12 inches in length, like Butties, Uarus, Jaguar Cichlids and Wolf Cichlids.

5. Walking Catfish

Scientific name: Clarias Batrachus

Max adult size: 2 ft / 24 inches / 61 cms

The walking catfish are remarkable fish, as they can breathe air directly from the atmosphere. They can also survive outside water for extended periods of time, as long as they stay moist. In the wild, they are known to hop out of their ponds and crawl their way to other nearby ponds.

6. ID Shark

Scientific name: Pangasianodon hypophthalmus

Max adult size: 4.5 ft / 53 inches / 134.6 cms

The ID shark or iridescent shark is not really a shark, but a catfish. It gets its name from the parallel iridescent stripes running along the length of the body. The placement of its fins reminds one of a shark.

7. Pangasius Catfish

Scientific name: Pangasius bocourti

Max adult size: 4.5 ft / 53 inches / 134.6 cms

Often confused with the iridescent (ID) shark, these giants are commonly eaten in East Asia. They have a similar body structure to the red tailed catfish. They are also called Basa Fish.

8. Red Tailed Catfish

Scientific name: Phractocephalus hemioliopterus

Max adult size: 6 ft / 72 inches / 182.8 cms

These are very stocky and beautiful fish, but unfortunately grow too large for tanks. Even most ponds are too small for them. For a tank-friendly fish that has similar contrasting colours, you can check out the red tailed shark. They have black bodies with striking red tails.

9. Tiger Shovelnose Catfish

Scientific name: Pseudoplatystoma fasciatum

Max adult size: 3.5 ft / 42 inches / 106.6 cms

This rather unusual looking catfish have a reputation for jumping out of aquariums. If you would like to keep something with similar patterns, you could check out the freshwater eels. They come in many different colours and patterns.

10. Ripsaw Catfish

Scientific name: Oxydoras niger

Max adult size: 3.5 ft / 42 inches / 106.6 cms

The name might lead one to believe that this is an aggressive fish. But it is very peaceful and gets its name from the bony plates running along either side of its body. They can be kept in large ponds.

11. Plecostomus

Scientific name: Hypostomus plecostomus

Max adult size: Upto 2 ft / 24 inches / 61 cms

Plecostomus, often called Plecos belong to the Catfish family and mainly eat vegetable matter. They are commonly sold when they are just 2-3 inches in size, and new aquarists are told that they live off the algae and uneaten fish food in a tank.

This is completely untrue, because Plecos have massive appetites, and even the biggest algae outbreaks in a tank will be taken care of in a few short days. After that, it will starve. And since they can survive weeks without food, the budding aquarists think that they are eating well, until the Plecos ‘suddenly’ die.

However, there are species that don’t grow more than 5-6 inches in length, so if you find out exactly which species you’re getting, you can keep a couple of them happy in a tank. Just be sure to feed them well!

12. Arowana

Scientific name: Osteoglossum bicirrhosum

Max adult size: Upto 4 ft / 48  inches / 122 cms

Arowana, also called Dragon Fish, are sought after for their beauty and are among the more expensive freshwater aquarium fish. The African Arowana are the larger species, while the Asian Arowana are relatively smaller, but still get up to 3 ft / 36 inches / 91.4 cms long, too large for a home fish tank.

13. Giant Gourami

Scientific name: Osphronemus goramy

Max adult size: Upto 2.3 ft / 28 inches / 71 cms

Unlike most other Gouramis which reach only a few inches in length, these are truly the giants of the Gourami world. They are often sold when they are very small, and they look like the smaller Gouramis, so a new aquarist may not expect them to get so big.

14. Pacu

Scientific name: Colossoma macropomum

Max adult size: Upto 3.5 ft / 42 inches / 106.6 cms

Pacu look very similar to their cousins, the Piranhas. They get huge, upto 3.5 ft in length and over 2 ft / 24 inches / 61 cms in height. Since they prefer to live in schools, anything other than large public aquariums will be too small for them. However, if you like the way they look, you can get Silver Dollars, which look like shiny silver Pacus, but only get to about 8 inches in length.

15. Bala Shark

Scientific name: Balantiocheilos melanopterus

Max adult size: Upto 1.16 ft / 14 inches / 35.5 cms

The Bala Sharks are relatively smaller than most fish on this list, so it may seem that it is possible to keep them in a large tank. However, they are shoaling fish which means they need to be kept in groups of at least 4.

In terms of care, think of them as massive minnows. Keeping this in mind, imagine the size of tank one would need to house 4 active and fast swimming fish, each over 1 ft in length!

16. High Fin Shark

Scientific name: Myxocyprinus asiaticus

Max adult size: Upto 4.5 ft / 54 inches / 137 cms

Also called the Freshwater Batfish and the Chinese High Fin Shark, they feed mainly on algae in the wild. While an aquarium is no place for them, they are peaceful and do well in large outdoor ponds and are great for controlling algae.

17. Alligator / Spotted Gar

Scientific name: Atractosteus spatula

Max adult size: Upto 6 ft / 72 inches / 182.8 cms

The Alligator Gar and Spotted Gars are both very striking to look at, with slender bodies making them look even longer than they really are. They also have unique mouths, like those of an alligator.

They are predators and feed primarily on live food. However, they get too large for home aquariums and shouldn’t be kept in a fish tank.

18. Knifefish

Scientific name: Apteronotus albifrons

Max adult size: Upto 1.6 ft / 20 inches / 50.8 cms

Most Knifefish species are tankbusters and get very large, although the Black Ghost Knifefish stays relatively smaller at about 1 ft / 12 inches / 30.4 cms in length, and can be kept in a tank.

However, all species of knifefish are very difficult to keep in a home aquarium and rarely eat anything other than live food. They are also very sensitive to water parameters and should only be kept by someone who has prior fish keeping experience.

19. Giant Snakehead

Scientific name: Channa micropeltes

Max adult size: Upto 5 ft / 60 inches / 152.4 cms

The Giant Snakeheads are very messy fish that eat a lot and create a lot of mess in the aquarium. If you really like snakeheads and would like to get them, there is a group of smaller species, called dwarf snakeheads, whose length ranges from 6 – 12 inches.

20. Peacock Bass

Scientific name: Cichla kelberi

Max adult size: Upto 1.5 ft / 18 inches / 45.7 cms

The Peacock Bass are often caught from rivers by individuals who keep them in their home tanks. They are voracious eaters and are very messy, requiring lots of water changes. There are different species of Peacock bass, with the smallest one being Cichla kelberi, which reaches upto 1.5 ft in length. The larger species reach well over 3 ft / 36 inches / 91.4 cms!

21. Mbu Puffer

Scientific name: Tetraodon mbu

Max adult size: Upto 2.5 ft / 30 inches / 76.2 cms

As with all species of puffer fish, the Mbu puffer needs a special diet of shelled creatures, like snails, crabs, crayfish, mussles, etc. The hard exoskeletons on these animals help to grind down the teeth or ‘beak’ as it is known. A puffer fish’s beak keeps growing all through its life, and can get very painful if left without proper care.

Puffer fish are very curious and interesting fish to watch, and although this one is too large for a home aquarium, there are much smaller species out there too. You can read about them here.

22. Araipama

Scientific name: Arapaima gigas

Max adult size: Upto 8 ft / 96 inches / 243.8 cms

There are some truly massive fish on this list, but then comes the Araipama, a giant among giants. They regularly cross 100 kgs / 220 lbs in weight, with the heaviest one on record being 200 kgs / 440 lbs!

They are carnivorous, so feeding a varied diet to just one of these fully grown monsters will cost more than feeding a family of 10 people! They belong only in the wild and the largest of public aquariums.

Syed Baseeruddin Hyder

I’ve been keeping fish and invertebrates in aquariums for over 5 years. Over the years, I’ve kept more than 15 different species of fish and invertebrates. Through ParadiseInATank.com, I hope to guide new and experienced fish keepers alike with as detailed information as I can get.

Recent Content