Species guide
Bristlenose Pleco Care Guide (vs Otocinclus)
Fish
Bristlenose plecos (Ancistrus) are the practical algae grazer for planted tanks — smaller than common plecos, bigger than otos. They need driftwood, vegetables, and an 80 L+ footprint. Not a substitute for a six-otos biofilm crew on a new tank.
- Algae grazer
- Needs driftwood
- 80 L+ tank
- Not otos
Quick facts
| Size | ~12–15 cm adult |
|---|---|
| Temp | 22–27 °C |
| pH | 6.5–7.5 stable |
| Diet | Algae + wood + blanched veggies |
| Wood | Required — digestive fiber |
| Tank | 80 L (20 gal) minimum solo |
| vs otos | Otos tiny school biofilm; BN one bigger fish |
| vs common pleco | Common pleco grows huge — not BN |
Overview
Bristlenose pleco is the planted-tank workhorse catfish. Otocinclus are nano schools for soft biofilm on mature tanks. Common plecos outgrow most scapes — BN stays manageable with wood and veggies.
Algae crew roundup: best algae eaters · shrimp: Amano. Cycle first: fishless vs fish-in.
Wood, veggies, space
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Step 1
Add driftwood before adding BN
They rasp wood — not optional decoration.
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Step 2
One BN per 80–120 L unless huge tank
Territorial with other BN at breeding size.
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Step 3
Feed blanched zucchini/cucumber after algae gone
Starvation if you expect them to live on glass algae alone.
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Step 4
Don't add to brand-new sterile tank like otos
Cycled tank yes — but still feed veggies.
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Step 5
Choose Ancistrus — verify not common pleco juvenile
Pet stores mislabel small commons as BN.
Common problems
Not eating algae
Why: Tank too clean — feed veggies.
Fix: Zucchini clip nightly; reduce wafers if fat.
Attacking plants
Why: Hungry or insufficient algae/veg.
Fix: Feed more; rare on well-fed BN.
White poop / thin
Why: Starvation or internal parasites.
Fix: Veg diet; quarantine if wasting.
Chasing other BN
Why: Breeding territory.
Fix: Second cave or rehome.
Tank mates
Gear for this species
Budget first community setup — BN pleco needs wood and veggies — not otos on a new tank
FAQ
Bristlenose vs otos?
BN one larger pleco on wood/algae. Otos school on biofilm — mature tank.
Need driftwood?
Yes — fiber and behavior.
Will BN eat plants?
Usually not if fed; hungry ones rasp soft leaves.
Tank size?
80 L minimum for one adult.
BN vs common pleco?
Common grows 30+ cm. BN stays ~12–15 cm.
Safe with shrimp?
Mostly yes — rare baby shrimp predation.
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