A compact, armored suckermouth catfish that stays far smaller than the common pleco, making it a practical algae-grazer for community tanks. Mature males sport distinctive branching tentacles across the snout.
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Stocky suckermouth catfish reaching about 10-13 cm (4-5 in); mature males grow fleshy facial bristles.
Lifespan
5–12 years
Social needs
solo
Native region
South America (Paraná / La Plata river basin; aquarium fish are typically captive-bred Ancistrus of mixed origin)
Origin
New World
Climate
🌴 Tropical
Water type
💧 Freshwater
Family
Loricariidae
Genus
Ancistrus
Part of the Catfish
Catfish are a diverse order of mostly bottom-dwelling fish, including peaceful shoaling corydoras, armored loricariids, and scavengers prized for keeping the lower levels of an aquarium active and clean.
From the minimum an animal needs to be kept humanely, up to the ideal setup. Bigger is almost always better — minimums are floors, not targets.
Photo coming soon
Minimum
Single adult tank
30 gal / 114 L planted
Ancistrus sp. tops out around 4–5 in. A 30-gallon planted tank is the practical minimum, with driftwood (required for digestion), caves for hiding, and strong filtration to handle their heavy waste.
Photo coming soon
Recommended
Community with caves
40 gal / 151 L long with caves
40-gallon long planted community with multiple caves, driftwood, and algae for grazing plus supplemental veggies. Single males or harem (1 M / 2 F) breed readily in well-fed setups.
Ideal
Planted breeding display
55 gal+ / 208 L+ planted
Planted 55-gal+ with extensive driftwood, multiple spawning caves, and consistent diet of veggies plus protein. Easy to breed, fry are hardy.
Emőke Dénes / CC BY-SA 4.0 (Wikimedia Commons)
Life & growth stages
How this animal changes through its life — each stage often has its own care, diet and space needs.
Photo coming soon
Egg
Fish eggs are small, translucent spheres, often laid in clutches on plants, substrate, or in a nest — or carried/brooded by a parent in livebearing and mouth-brooding species. A dark eye spot and the curled embryo become visible inside as development progresses.
Photo coming soon
Fry
Newly hatched fry are tiny and semi-transparent, frequently still carrying a yolk sac that fuels them before they feed freely. They lack full fin structure and adult coloration, staying near cover until they can swim and forage on their own.
Photo coming soon
Juvenile
Juveniles look like miniature adults but with developing fins and muted or different markings; many species shift pattern and color as they mature. Growth is rapid at this stage given clean water and steady feeding.
Adult
Adults show the species' full size, finnage, and mature coloration, and are sexually mature. Many fish develop sex-specific differences in size, color, or fin shape, which can intensify during breeding.
Color & pattern variants
Natural variants occur in the wild; selectively bred (man-made) variants were developed in captivity.
A single adult needs a tank of at least 75-115 litres (20-30 US gal); they are largely solitary and males become territorial, so give each fish its own cave if keeping more than one. Provide driftwood (which they rasp and need for digestion), smooth rocks, caves, and a sand or smooth-gravel substrate, plus plenty of hiding places, as they are shy and mostly nocturnal.
They are tropical: keep water at 23-27 C (73-81 F), pH 6.5-7.5, soft to moderately hard, with strong filtration and good oxygenation because they are messy, high-waste fish. Regular water changes are essential to control nitrates from their heavy grazing and waste output.
Substrate
Sand or smooth rounded gravel is ideal so they can graze without scratching; avoid sharp substrate. They thrive in tanks with plenty of driftwood, which they rasp on for fiber.
Equipment & setup
A tank of 25+ gallons with strong filtration and good oxygenation, a heater at 73-80F, and at least one piece of real driftwood. They tolerate a wide pH range but need clean, well-aerated water given their bottom-dwelling, high-waste lifestyle.
Diet
Primarily herbivorous algae-grazers that also need supplemental food: algae wafers, spirulina, and blanched vegetables such as zucchini, cucumber, spinach, and sweet potato. A clean tank often does not provide enough algae, so they must be actively fed rather than left to scavenge.
Driftwood is a dietary requirement, not just decor; they rasp wood fibre that aids digestion. Offer occasional protein (sinking pellets, the odd frozen food) but keep the diet plant-heavy. Feed in the evening when they are most active, and avoid overfeeding vegetables that can foul the water.
Behavior & temperament
Peaceful toward other species but males are territorial with each other and will defend a cave, especially when guarding eggs. They are nocturnal and reclusive by day, becoming active grazers after dark. They make excellent community algae-control fish and ignore tankmates entirely.
Enrich the tank with caves, driftwood, and shaded retreats so each fish has a secure territory. In breeding setups the male guards and fans the eggs inside a cave. Provide low-traffic resting spots and dim or planted cover to bring out natural foraging behavior.
Health
Common issues stem from poor water quality given their heavy bioload: ammonia or nitrite spikes, fin rot, and ich. Strong filtration, frequent water changes, and not overstocking prevent most problems. They are sensitive to copper-based medications, so treat cautiously.
Malnutrition and constipation occur when they lack vegetables or driftwood; a sunken belly signals starvation, a swollen one signals bloat. Quarantine newcomers for parasites, keep nitrates low, and ensure a varied, fibre-rich diet to maintain long-term health.
Tips, DIY & hacks
Always include bogwood/driftwood since they require the wood fiber for digestion, and supplement grazing with blanched zucchini, cucumber, and sinking algae wafers (they do not survive on tank algae alone). Provide a PVC pipe or cave hide; males guard caves and will spawn and fan eggs inside them.
