Bristlenose Pleco (Common Bristlenose)
Ancistrus cirrhosus
Ancistrus cf. cirrhosus is a small Loricariid catfish known for its sucker mouth, armored body plates, and the distinctive facial bristles (especially prominent in adult males). It is primarily nocturnal and spends much of its time grazing on biofilm and algae from surfaces, making it a popular, hardy "algae-eater" in community aquariums.
The Bristlenose Pleco features a flattened body, dark brown to light tan coloration, and distinctive bristle-like appendages on mature males.
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Quick Facts
Size
5 inches
Temperament
Peaceful
Difficulty
Beginner
Min Tank Size
30 gallons
Lifespan
8-12 years
Origin
South America (often aquarium-trade/tank-bred; wild Ancistrus cirrhosus listed from Paraná River basin)
Diet
Omnivore with strong herbivore tendency - algae/biofilm, sinking wafers, blanched vegetables (zucchini, spinach), plus occasional meaty/frozen foods
Water Parameters
22-27°C
6-7.5
2-20 dGH
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Calculate heater sizeCare Notes
- Provide a well-oxygenated freshwater tank with strong filtration and steady flow, plus plenty of driftwood, caves, and shaded hiding spots; driftwood is especially useful for grazing and helps support normal digestion.
- Maintain stable, clean water: aim for ~22-27°C, pH ~6.0-7.5, and low-moderate hardness; keep ammonia/nitrite at 0 and nitrate low via regular water changes and good filtration.
- Feed primarily plant-based foods (algae wafers, sinking herbivore pellets, blanched zucchini/cucumber/green beans/spinach) and supplement 1-2× weekly with small amounts of protein (e.g., shrimp pellets) to support growth without bloating.
- Bristlenose plecos are generally peaceful community fish, but adult males can be territorial with each other, so keep one male per tank unless the aquarium is large with multiple caves and line-of-sight breaks.
- Choose tank mates that are not aggressive fin-nippers and won't outcompete them at night; avoid large predatory cichlids and be cautious with very fast bottom feeders that can starve them of sinking foods.
- Breeding is straightforward in freshwater: provide a snug cave/tube, keep water warm and clean, and the male will guard eggs and fry; feed fry with crushed algae wafers, soft vegetables, and biofilm until they grow.
- Watch for common issues like stress from poor oxygenation, starvation (sunken belly), bloat/constipation from too much protein, and skin irritation from sharp decor; quarantine new fish and avoid using copper-based medications unless verified safe for catfish.
Compatibility
Good Tankmates
- Peaceful community schooling fish (tetras, rasboras, danios) that ignore bottom territories
- Livebearers (platies, mollies, swordtails) in similar water conditions; generally non-territorial toward plecos
- Corydoras and other peaceful bottom fish in adequately sized tanks with multiple hides and food spread out
- Dwarf cichlids with mild temperaments (Apistogramma, Bolivian ram) if plenty of caves/wood reduce territorial disputes
- Adult freshwater shrimp and snails (Amano, Neocaridina, nerites) usually work; shrimp fry may be at risk
Avoid
- Large, aggressive cichlids (Oscars, jaguars, Texas cichlids) that may harass, injure, or outcompete plecos
- Highly territorial bottom-dwellers and plecos in tight quarters (multiple plecos, aggressive loricariids) that compete for caves/food
- Bettas (and other slow, long-finned fish) can be risky; plecos may rasp slime coats in some cases, especially in cramped tanks or when underfed
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