Arapaima Fish – Habitat, Care, Feeding, Tank Size, Breeding

The arapaima fish, also known as Paiche or Pirarucu, is one of the largest freshwater fish species in the world. It can reach lengths of 15 feet and weigh up to 440 pounds in the wild. In aquariums, the arapaima will average at around 23 inches in length.

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The arapaima’s streamlined body is black with a white center and red tails. The name pirarucu is a rough translation of ‘red fish’ in the Tupi language. Their bodies are lined with scales while their head is copper-greenish.

The fish are also obligate air breathers, and they can only stay underwater for 10 to 20 minutes. A modified swim bladder that opens into its mouth functions as a lung. The fish are scarce, mainly because their wild population has been on a decline.

They are also pricey if you do manage to get one, but ensure that they are sustainably sourced. Their trade can also be restrictive, depending on your country. There is a concern about the introduction of these fish in non-native habitats if they outgrow an owner’s aquarium.

Arapaima Fish Habitat

The arapaima was first described in 1882 by Schinz. Populations were discovered across the Amazon River Basin, although their specific habitat is still unknown. The fish also migrates from season to season.

During the dry season, the arapaima moves to rivers and lakes and migrates to flooded forests in the wet season. The fish can survive in oxygen-deficient areas due to its ability to breathe.

The ability of the arapaima to survive in piranha-infested waters has puzzled researchers. The scales of the fish have proven to be exceptionally resistant to predation in the form of piranha bites.

The scales are not only tough, but they are also very flexible which helps the fish to maneuver in the water.

A scientific study established the scales of the arapaima as the toughest flexible material in nature. The outer layer is more mineralized than the bone, which makes it more resilient.

The inner layer is softer, and it consists of a collagen fibril. These fibrils will deform along various angles and prevent a crack on the outer layer from growing. These scales are strong enough to break piranha teeth.

The arapaima is a popular food in South America since over 50% of its body weight consists of meat. This meat is boneless, and its popularity has made it illegal to harvest it in countries like Guyana.

Overharvesting has also drastically reduced the populations and size of wild arapaima fish. The fish are easy to catch because they frequently come up for air and take it in with a cough that can be heard by fishermen.

Finding full-grown arapaima in the wild has become tasking for biologists. The fish has recently been introduced to Eastern Asia for fishing.

Arapaima Fish Tank Requirements

The arapaima’s large size makes it a bit challenging to keep. It needs a minimum of 1,000 gallons with a 2500-gallon aquarium being ideal.

Arapaima is best suited for public aquariums, or for aquarists who are experienced in keeping monster fish.

The fish is a surface and middle dweller, and it demands a lot of swimming space. You can use some floating plants, but they should occupy only a small portion of the water’s surface.

The fish are air breathers, and you need to leave enough space between the surface of the water and the aquarium top. The cover should be tight since they are skilled jumpers.

The arapaima fish thrive in wide tanks with vented canopy-type tops. Use a fine gravel substrate and an effective aeration system.

The tank can be thickly planted on the sides and back, but leave a lot of areas open for swimming.

You can use moderate to normal lighting as the fish is not fussy about lighting requirements.

Arapaima Fish Water Conditions

Keep a temperature and pH range of 75-84 °F and 6.0-6.5, respectively. The ideal water hardness range is 5-12 dGH.

Arapaima tanks should be equipped with large filtration systems that can keep up with the bio-load of the fish. Change 15-20% of the water every week to maintain water quality.

If these conditions are not met, the arapaima will be vulnerable to skin flukes, parasitic infections, and bacterial disease. The risk of disease is higher among the fish because they eat live food.

You should,therefore, source their meals in reputable sources or grow them yourself in ponds. The arapaima fish are, however, hardy, and diseases are rarely an issue in well-maintained tanks.

Arapaima Fish Diet & Feeding Schedule

Wild arapaima fish depend on a carnivorous diet of either meat or fish. They will snatch birds from low-hanging branches thanks to their impressive jumping skills.

The fish likes to stalk prey on the water’s surface but it will also dive down into the water to catch aquatic animals. It will feed on amphibians, waterfowl, smaller mammals, and invertebrates.

In captivity, arapaima fish will eat pellets, crustaceans, plankton, krill, and live foods.

Arapaima Fish Tank Mates

The arapaima are notably aggressive to members of the same species and should be kept singly. They are gifted predators, which means that any smaller fish will become instant prey.

If you are growing out the arapaima in a large tank, you can include similarly-sized aquatic fish and ensure that all of them can establish territories. It is best to keep the arapaima alone.

Arapaima Fish Breeding

The reproduction cycles of wild arapaima are affected by the dry and wet seasons. They construct their nests from February to April when the water levels are low.

The nests are set up in a sandy area that is around six inches deep and 20 inches wide. Both parents protect the eggs and the fry, and the young arapaima stay with their parents until they are about three months old.

Arapaima fish are a mouth-brooding species, and they aerate the eggs because they live in oxygen-depleted regions. The adult exudes a pheromone from their head to communicate with their young.


The arapaima fish a monster freshwater species that is ideally suited for large aquariums like public zoos. They are quite pricey and they will require the largest filtration system available.

The fish is a loner, and it will attack tankmates of the same species. Keep them alone and leave plenty of swimming space.

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