The name "plec" covers a large number of catfish species, so it's a good idea to know which one you are getting. That being said, there are some general guidelines for the care of these nocturnal fish.
Plecos do not do well with others of the same species unless there is a considerable amount of space. They are extremely territorial, but get along well with other types of fish. They can grow up to 2 feet long, so most aren't a good choice for small aquariums. They are generally sold while only a few inches long, but can live for up to 20 years, growing each year. The most common reason to add one of these fish to your aquarium is to combat algae growth, since they eat this as their base food.
Aquarium Setup and Feeding
To ensure that your fish is healthy and happy, you should decorate your aquarium. They need wood to chew on, so a piece of a log that can also be used to hide in during the day is a good choice. It's also important to vary their diet. While a pleco will eat the algae in the tank, they need more than this. Feed them vegetables such as peas, lettuce and zucchini, as well as the occasional brine shrimp to keep them healthy.
Plecos are very easy to care for, as long as they have lots of places to hide and you make sure they are getting more than just algae to eat. Since they are nocturnal, it's not uncommon for the other fish in the tank to eat everything up before your catfish gets it. Apart from that, they serve a valuable purpose and are quite laid back fish.