Plecos

Plecos are the most misunderstood fish in the freshwater hobby. They are sold as algae cleaners, and most of them are not. They are sold at three inches, and some of them reach eighteen. We would rather you knew which one you are buying.

The common pleco problem

A common pleco (Pterygoplichthys) grows to 18 inches or more and lives well over a decade. It needs a very large tank, produces an enormous amount of waste, and stops eating algae almost entirely once it matures. If you want a fish that handles algae in a normal-sized aquarium, you want a bristlenose — they top out around five inches, stay interested in algae their whole lives, and are genuinely easy to keep.

L-numbers, decoded

When a pleco is collected and traded before it has been formally described, it gets an L-number instead of a species name — L134 for the leopard frog, L046 for the zebra. The numbers are catalogue entries, not grades, so a higher number does not mean a better fish. What they do tell you is that the species is often wild-collected, which matters: many of the prized L-numbers want soft, warm, fast-moving, highly oxygenated water and will not thrive in a slow, warm community tank.

They are not a cleanup crew

Even the algae-eating species need to be fed. A pleco relying on whatever grows in the tank is a slowly starving pleco, and it is the most common way they are lost. Sinking wafers, blanched vegetables and, for the wood-eating Panaque group, real driftwood they can rasp on — that last one is a dietary requirement, not decoration.

Our rarer plecos are held at the Mid-City store. More on what we stock at Rare Plecos San Diego.