What is a small fish with armored plates all over their bodies?

A small fish with armored plates all over its body is likely a species of Plecostomus, commonly known as a pleco. These Freshwater Fish are often found in rivers and streams in South America and are known for their distinctive bony plates, which provide protection from predators. They are popular in aquariums for their algae-eating habits and come in various species, some of which can grow quite large. Another example is the catfish, specifically the armored catfish, which also possesses a similar protective plating.