Fish Most active at dawn and dusk

Freshwater Catfish

Tandanus tandanus

iNaturalist Wikipedia

A master of the riverbed, the Freshwater Catfish is famous for its eel-like tail and its incredible skill as an underwater architect. This whiskered Australian native is a fascinating subject for any underwater backyard observer.

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Quick Identification

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Size

30-50 cm (12-20 in) on average, reaching up to 90 cm (35 in); weighs 1.5-3 kg (3-7 lbs), occasionally up to 7 kg (15 lbs)

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Colors

Mottled olive-green, brown, or purplish-black upper body with a cream or white underbelly; juveniles are often more brightly mottled

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Key Features

Eel-like tail tapering to a point
Four pairs of sensory barbels (whiskers) around the mouth
Scaleless, slimy skin with a thick mucus layer
Venomous serrated spines on dorsal and pectoral fins

When You’ll See Them

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Activity pattern Most active at dawn and dusk

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Peak hours 6 PM - 1 AM

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Season Year-round; most active during warmer spring and summer months

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Diet Opportunistic carnivore; forages along the bottom for shrimp, crayfish, snails, aquatic insects, and small fish.

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Habitat Prefers slow-moving rivers, lakes, billabongs, and ponds with sandy or gravelly bottoms and plenty of submerged cover.

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Where Does the Freshwater Catfish Live?

The Freshwater Catfish is a quintessential Australian species, primarily native to the vast Murray-Darling river system that spans much of the continent's southeast. Beyond this massive basin, they are naturally found in coastal river systems from the eastern tip of the Cape York Peninsula in Queensland all the way down to central Victoria. While they are eastern specialists by nature, human intervention has expanded their footprint, with populations now established in various farm dams and waterways in Western Australia. They prefer the slower, steadier pulses of inland rivers and the tranquil environments of coastal lagoons and billabongs.

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1 Countries

1.2M km² Range

Least Concern Conservation

AU Australia

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iNaturalist / Verified observation data

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Behavior

The Freshwater Catfish, often called the 'Tandan,' is a hardy, bottom-dwelling species known for its unusual appearance and industrious nature. Unlike many other catfish, it possesses a continuous fin that runs along its back and around the tail, giving it an eel-like silhouette. They are generally solitary and shy, spending their daylight hours tucked away in hollow logs, undercut banks, or among aquatic vegetation. As dusk approaches, they become much more active, using their sensitive barbels to 'taste' the substrate and locate prey in low-light conditions.

One of their most remarkable behaviors is their nesting ritual. During the breeding season, the male becomes an architect, meticulously clearing a circular area of the riverbed and carrying pebbles and gravel in his mouth to construct a mound-shaped nest. He then stays to guard the eggs and fanned them with his fins to keep them oxygenated. While they are generally peaceful, they can be territorial during this period and will use their venomous spines as a last resort defense if threatened by predators or handled carelessly by humans.

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Camera Tips

Capturing the Freshwater Catfish on camera requires a specialized approach since they are entirely aquatic. If you have a backyard pond or live near a creek, an underwater action camera or a waterproof trail camera is essential. Position your camera on a weighted tripod or secure it to a heavy submerged log, aiming the lens toward sandy or gravelly clearings. This species is most active at night and during the twilight hours, so ensure your camera has high-quality infrared (IR) night vision to cut through murky water without spooking the fish.

To attract a Freshwater Catfish to your lens, place a small mesh bait bag filled with smelly attractants like prawns, worms, or crushed snails just inside the camera's field of view. Be sure to secure the bait bag to a fixed object so the fish doesn't drag it out of frame. If you are filming in a river, aim the camera slightly downstream to prevent floating debris from collecting on the lens, and try to find a spot with slow-moving water or a deep pool where catfish congregate during the day.

Spring and early summer are the best times for filming unique behaviors. During this period, males become industrious architects, clearing circular depressions in the riverbed and carrying pebbles in their mouths to build nests. If you spot a mound of gravel about 50cm to 100cm wide in the shallows, place your camera nearby at a respectful distance. You may capture the fascinating parental care and nest maintenance that makes this species so unique among Australian fish.

Similar Species

Species that look similar or are commonly confused with Freshwater Catfish.

Hyrtl's Catfish

Smaller in size with a shorter dorsal fin and usually found in more northern, tropical waters.

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Frequently Asked Questions

Freshwater Catfish are primarily crepuscular and nocturnal, meaning they are most active during the twilight hours of dawn and dusk, as well as throughout the night.

They are attracted to structure and food. Providing submerged logs or pipes for cover and using protein-rich sinking pellets or natural baits like earthworms can encourage them to stay in view of your camera.

They are benthic carnivores that eat a variety of small aquatic animals, including freshwater shrimp, crayfish, snails, and insect larvae.

Yes, they are common in suburban lakes, farm dams, and slow-moving creeks throughout eastern Australia, provided the water quality is reasonable.

The Freshwater Catfish (Tandanus tandanus) has a much longer second dorsal fin that starts further forward on the body compared to the Hyrtl's Catfish, and it generally grows to a much larger size.

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