<a href=showthread.php?s=&postid=10424991#post10424991 target=_blank>Originally posted</a> by EdKruzel
That label is a misnomer as any fish in an unsuitable container will contract disease or parasites. Some fish such as clowns are actually better off in a home aquarium then in the sea. Their territories are small and can be duplicated in most average or large tanks, but without predators while their meals are always delivered; no more hunting. With nominal care, many report a lifespan of over 20yrs with some going over 40yrs.
On the other side of the spectrum we have tangs which in the wild start a territory of no less than a large apartment up to nearly an acre. Tangs for the most part are peaceful in nature, but even with such large grazing territories, you will notice them attack rival schools or other grazing species when on their patch of algae. The diet is easy to duplicate, but the level of water purity and high oxygen content are a bit more challenging. It always amazes me that someone who has kids or dogs or cats, or just about any land pet will spend huge amounts of money and search frantically within the environment for a cause if the above mentioned becomes ill (and you should, it's called compassion) but when their fish contract parasites, it's written off as the damn fish is an ich magnet.