Harlequin Lancer Catfish
Siluriformes sp.
The Harlequin Lancer Catfish (Siluriformes sp.) is a peaceful fish that's easy to keep. Give it a tank of at least 455 litres (120 US gallons), water held at 75-81°F, and a pH of 6-7.8.
Captive lifespan reflects typical experience in a home aquarium, not maximum recorded age; genetics, sourcing, and care vary.
Natural distribution
Mostly South America / Africa
- South America
- Africa
Regional colours match the stocking calculator's origin map.
Harlequin Lancer Catfish Tank Setup
Plan for at least 455 litres (120 US gallons) with soft sand or smooth, rounded gravel - sharp substrate wears down their delicate barbels. Keep the water at 75-81°F with a pH around 6-7.8. They grow to around 30 cm, so plan the tank size and filtration for a full-grown adult rather than the small juvenile you see in the shop.
What Do Harlequin Lancer Catfish Eat?
They're bottom feeders, so give them sinking wafers, tablets, or frozen treats like bloodworm once the lights go down. Flakes that never reach the bottom leave them hungry even when the tank looks well-fed.
Harlequin Lancer Catfish Tank Mates
Requires a large tank and good filtration. The Harlequin Lancer Catfish is peaceful, which is the first thing to weigh up when you choose tank mates. At around 30 cm fully grown, it needs tank mates that can hold their own against its size and appetite. Before you buy, run your full stocking list through our stocking calculator. It weighs temperament, adult size, and water needs together, which a single species page can't do on its own.
Are Harlequin Lancer Catfish Good for Beginners?
Reasonable early choice after cycling. Buy after the tank has stable ammonia and nitrite readings, not the same weekend you fill it.
Harlequin Lancer Catfish - frequently asked questions
What size tank do Harlequin Lancer Catfish need?
Harlequin Lancer Catfish need a tank of at least 455 litres (120 US gallons). A bigger tank is always easier to keep stable, and gives them more room to settle in and behave naturally.
What water parameters do Harlequin Lancer Catfish need?
Keep them at 75-81°F with a pH of 6-7.8, steady rather than chased to an exact figure. In a cycled tank, ammonia and nitrite should both read 0 ppm, with nitrate kept low through regular water changes.
What do Harlequin Lancer Catfish eat?
Harlequin Lancer Catfish are bottom feeders. Give them sinking wafers, tablets, and frozen foods that settle on the substrate, ideally after the lights go off. Feed small amounts once or twice a day, and remove anything they don't eat.
Are Harlequin Lancer Catfish good for beginners?
Yes - Harlequin Lancer Catfish are a reasonable beginner fish once the tank is cycled and parameters are stable. Add them after ammonia and nitrite read 0 ppm, not the same day you fill the tank.
Common mistakes with Harlequin Lancer Catfish
- Underestimating tank size - the minimum footprint is 455 litres (120 US gallons); impulse buying into a smaller tank leads to stress and shortened lifespan.
Building a community? Run the full list through the stocking calculator before you add anything else.
Great tank mates
Chosen from temperament, overlapping temperature/pH bands, plausible minimum tank footprints, and size versus yours in App-aquatic data. Hobby nuance always wins - verify stocking and temperament before purchasing.
Fish to avoid mixing with Harlequin Lancer Catfish
These well-known species are commonly sold alongside this fish but are not recommended tank mates - verify before purchasing.
- OscarPredator - Oscar will eat or injure smaller tank mates
- Pea PufferPredator - Pea Puffer will eat or injure smaller tank mates
- Betta (Male)Predator - Betta (Male) will eat or injure smaller tank mates
