Sisoridae (Asian hillstream catfishes)

Crocodile Catfish

Bagarius suchus

Bagarius suchus, known as the Crocodile Catfish, belongs to the family Sisoridae, or Bagridae (mountain catfishes). This large predator is characterized by a complex temperament. Its keeping, if undertaken independently, requires significant expense and effort. In the aquarium hobby, it is rarely encountered among enthusiasts and is not suitable for beginners.

Tank
from 1000 L (264 gal)
Temperature
18 – 23 °C (64 – 73 °F)
Size in aquarium
65 – 70 cm (26 – 28 in)
Acidity
pH 6–7.5

Predator: dangerous to small fish

Natural rangeRange on the map
  • Mekong River Basin
  • Chao Phraya River Basin
  • Laos
  • Thailand

Tank conditions

Plan the tank stocking
Temperature
18 – 23 °C (64 – 73 °F)
Water pH
Slightly acidic (6) – Neutral (7.5)
Water dH
Very soft (2) – Hard (12)
Water salinity
no salt (freshwater)
Size in aquarium
65 – 70 cm (26 – 28 in)
Lifespan
10 years
Temperament
Aggressive Aggressive / incompatible / unfriendly
Toward small fish
predator
Required aquarium volume
from 1000 L (264 gal)
Lighting
dimmed
Substrate
sandy (regular, light)
Water flow
moderate or strong
Swimming level
near the bottom
Feeding
Meat / protein live, frozen, fresh
Keeping
Solitary
  • Lifespan. A lifespan to expect under good care, not a measured value: it depends heavily on tank volume, water quality and diet — and for selectively bred forms, on their origin as well.
  • Toward small fish. Based on the Predators category in the catalog or the temperament in the species parameters. “A risk to small fish” means the species is not a predator by habit, yet will swallow any fish that fits in its mouth.
  • Required aquarium volume. This is a husbandry recommendation, not a measured value: the volume depends on the keeping mode (solitary), footprint, decor and tank mates.

Care and keeping

Description

Adult Crocodile Catfish can reach a length of up to 65–70 cm. The fish's body is straight, somewhat flattened, and its head is very narrow. Two massive pairs of barbels are located near the mouth. This structure allows the catfish to easily penetrate crevices between boulders in search of food and effectively resist strong currents. Its coloration is light brown, covered with black spots. Thanks to this camouflage, it is difficult to spot against a sandy bottom.

Habitat

Its natural habitat is Southeast Asia, specifically the basin of the extensive Mekong River, which flows through Thailand, Laos, and Cambodia. It can also be found in the Chao Phraya River and its tributaries, located in Thailand. In nature, this species prefers main channels with fast, sometimes turbulent currents, where it finds shelter among large boulders and rocks.

Behavior and Compatibility

Selecting compatible species is a challenging task, given this catfish's predatory diet. Furthermore, it is not particularly tolerant of conspecifics and other bottom-dwelling fish that may encroach on its aquatic space.

Care and Maintenance

Due to the significant size of this fish, the aquarium for it should have a volume of at least 1000 liters. Within it, a strong current and a high level of dissolved oxygen must be maintained. It is also important to ensure the stability of the water's hydrochemical composition and temperature within acceptable limits, and to prevent the accumulation of organic waste. The aquarium's decor should mimic its natural habitat — subdued lighting and several shelters on a sandy substrate. These are just some of the main tasks that an aquarist who decides to keep a Crocodile Catfish will face. The installation and subsequent maintenance of such an aquarium (whose total weight with water can exceed a ton) involve significant financial investment. This includes not only the acquisition of expensive equipment and the tank itself, but also the execution of construction work, as well as the installation of engineering systems for automating many processes. For example, for water treatment and the regular renewal of 50–70% of the water in the aquarium.

Diet

As a predator, the catfish feeds on small fish, amphibians, crustaceans, and other invertebrates. In a home aquarium, its diet can consist of similar products, or alternative fresh or frozen foods. These include bloodworms, earthworms, chopped shrimp, and shelled mussels. Specialized commercial foods developed for carnivorous species will also be a good choice. They must not be fed mammalian or avian meat: the lipids it contains cannot be properly metabolised by the fish and lead to excess fat deposits and even organ degeneration.

Breeding and Reproduction

Breeding of the crocodile catfish in aquarium conditions has not been recorded to date. In nature, this species is oviparous and migrates to spawn in deep river channels with strong currents. Given the specific habitat requirements and complex reproductive behavior, simulating the breeding process in captivity is considered practically impossible.

Diseases

Most health problems in fish often arise from unsuitable keeping conditions. Maintaining a stable and comfortable habitat is a key factor for successful keeping. If symptoms of illness appear, the first step is to check the water quality. If deviations are found, it is important to take immediate measures to eliminate them. If the symptoms do not disappear or worsen, medicinal treatment may be required.

How to choose

When purchasing a crocodile catfish, it should be noted that this is a rare and large predator requiring specific conditions. The main criteria for choosing a healthy specimen are: — absence of visible damage, ulcers, or white film on the body and fins, which often occur during transportation or due to poor water quality; — activity of the fish in the evening, as it is a crepuscular species; lethargy or apathy may indicate stress or exhaustion; — intact barbels, which are an important sensory organ; — clear breathing without frequent gill cover movement, which indicates no problems with water oxygen saturation. Before purchasing, it is important to ensure that the fish is adapted to non-live foods (frozen seafood or fish fillets), as feeding exclusively live fish increases the risk of introducing infections and parasites into the aquarium. Due to high sensitivity to water quality, it is recommended to clarify the keeping conditions in the store and avoid specimens kept in overcrowded or poorly filtered aquariums.

Compatibility

There are no pair reviews for this species yet — check tankmates in the matcher.

All tankmates

Plants and this fish

Matching water does not mean the plant will stay intact.

Frequently asked questions

The essentials: size, tank volume, water parameters and care

How big does Crocodile Catfish get?

An adult reaches 65–70 cm in length. Plan the tank around the maximum size: the fish quickly outgrows a cramped setup.

What size aquarium does Crocodile Catfish need?

The recommended volume is 1000 L. A smaller tank speeds up nitrate build-up and raises stress levels.

What water parameters does Crocodile Catfish need?

Temperature 18–23 °C, pH 6–7.5, hardness 2–12 dGH. Stability matters more than exact values: sudden swings are harder on the fish than a small deviation from the ideal.

How long does Crocodile Catfish live?

Around 10 years when kept properly. Lifespan depends directly on tank volume, water quality and a varied diet.

Is Crocodile Catfish aggressive?

Temperament: aggressive / incompatible / unfriendly. This is a predatory species — any fish small enough to fit in its mouth will eventually be eaten.

How many Crocodile Catfish should be kept together?

Recommended setup: solitary. Ignoring this is a common cause of stress and disease.

What does Crocodile Catfish eat?

Diet type: meat / protein (live, frozen, fresh). Feed small portions that are finished within a couple of minutes — overfeeding does more harm than underfeeding.

What is the scientific name of Crocodile Catfish?

The scientific name of the species is Bagarius suchus, family Sisoridae (Asian hillstream catfishes).

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Other scientific names and conservation status

Conservation status
Near threatenedNT