An average clownfish living in captivity will survive for 3-5 years. In the wild this would be considered a younger fish as their life span can reach 10+ years.
The most common cause of a short lifespan in captivity is death due to stress. If you or I feel stressed it’s not that big of a deal, But to clownfish, it’s a deadly condition.
One of the best ways to extend a clownfishes life is by providing it an adequate environment to thrive in. This includes freshwater, A sea anemone that is compatible with your species of clownfish. You should have a minimum of 1 female and 1 male in a tank as they like to be in pairs. Be sure you’re tank is of adequate size to avoid the occasional spousal squabble.
The longest living clownfish in captivity are over 20 years old and belong to the sub species amphiprion ocellaris.