The age of a 2 inch pleco is dependent on the species of pleco in question. Generally speaking, most small plecos grow to around 4-6 inches when fully mature, so a 2 inch pleco is likely still quite young. Some species can live up to 20 years or more and continue growing throughout their lifetime, meaning that it could be anywhere from 1–15 years old depending on the type of fish. It is important to do research into the specific type of pleco you have in order to give them the best care possible as different species will require different tank sizes and diets. Additionally, if you are unsure how old your fish may be it’s always best to consult an experienced aquarium keeper or veterinarian for advice.