Ancistrus sp. (Longfin)
Ancistrus sp.
The Ancistrus sp. (Longfin) (Ancistrus sp.) is a peaceful fish that's easy to keep. Give it a tank of at least 80 litres (21 US gallons), water held at 70-81°F, and a pH of 6-7.5.
Captive lifespan reflects typical experience in a home aquarium, not maximum recorded age; genetics, sourcing, and care vary.
Natural distribution
South America
- South America
Regional colours match the stocking calculator's origin map.
Ancistrus sp. (Longfin) Tank Setup
Plan for at least 80 litres (21 US gallons) with soft sand or smooth, rounded gravel - sharp substrate wears down their delicate barbels. Keep the water at 70-81°F with a pH around 6-7.5. They reach about 12 cm as adults, so don't be misled by the small juveniles sold in stores.
What Do Ancistrus sp.s 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.
Ancistrus sp. (Longfin) Tank Mates
Longfin Bristlenose; excellent algae eater. Males develop prominent bristles. Cave spawner; easy to breed. The Ancistrus sp. (Longfin) is peaceful, which is the first thing to weigh up when you choose tank mates. Good matches come down to the whole stocking list working together - temperature, tank size, and temperament - not any single label. 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 Ancistrus sp.s 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.
Ancistrus sp. (Longfin) - frequently asked questions
What size tank do Ancistrus sp.s need?
Ancistrus sp.s need a tank of at least 80 litres (21 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 Ancistrus sp.s need?
Keep them at 70-81°F with a pH of 6-7.5, 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 Ancistrus sp.s eat?
Ancistrus sp.s 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 Ancistrus sp.s good for beginners?
Yes - Ancistrus sp.s 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.
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 Ancistrus sp.s
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
