organism
Bristlenose pleco vs common pleco
Both are sold as small algae eaters. What is the difference?
Short answer
About 30 centimetres of adult length. The bristlenose stops around 12–15 cm and stays an effective grazer; the common pleco reaches 35–50 cm, produces an enormous waste load and largely stops eating algae as it grows.
Side by side
| Dimension | Bristlenose pleco | Common pleco | Favours |
|---|---|---|---|
| Adult size | 10–15 cm | 35–50 cm | Bristlenose pleco |
| Minimum tank | About 110 L | 800 L and up | Bristlenose pleco |
| Algae eating as an adult | Continues | Largely stops | Bristlenose pleco |
| Waste output | Substantial | Very high | Bristlenose pleco |
| Lifespan | 6–12 years | 10–20 years | — |
| Breeds in aquaria | Readily | Effectively never | Bristlenose pleco |
| Rasps the flanks of flat-bodied fish | When underfed | When underfed | Neither |
| Invasive risk if released | Lower | High — established populations cause bank erosion | Bristlenose pleco |
Which to choose
Bristlenose pleco
Choose the bristlenose. In almost every case where a common pleco is being considered, this is the right animal.
Common pleco
The common pleco only makes sense in a very large tank with filtration to match, chosen deliberately for the fish itself.
One caveat
Both need driftwood and both need supplementary vegetable food. Neither is a substitute for fixing whatever is causing the algae.