My clownfish pair are 19 years old in my care. The male is developing many dark spots. Like age spots now. Hope that is not a bad sign. But he is an old little guy.
Here are a few pictures of my 19 year old clowns I took this evening. I personally don't know anyone with any older but I am sure there are some out there in captivity. Oh and don't mind the tank, it is a mess
I've had my clowns for just over 4 years. The female has been getting darker with age around her dorsel fin. The male is still not quite as dark.
As to size, I saw a clown that was almost the size of my palm. One word... Huge compared to mine.