My Maroon clowns I got when my daughter was 1 or 2, so I guess I've had them about 19 years. They still seem pretty damned healthy, but they only lay eggs rarely now. There was a span of probably 13 years when they laid every 2 weeks. I have two damsels that are just a bit older than the clowns. I lost a lot of fish a few years ago when someone gave me a pair of fish that I added without quarantine. They could not be quarantined because they were obligate coralivores. That was a big mistake. If you want to have fish live a long time once you have a stable system STOP adding fish for years. It's the diseases that come in with new fish that are always the problem.
IME, some fish just do not have very long lifespans. Banggai cardinals usually don't go beyond 5 years. Anthias about the same, maybe a little more if you feed them a LOT, depends a lot on the species. Large angels can live for more than 10 years easy, as can lots of large fish (tangs, etc.). I agree on the wrasses thing...tend to have fast short lives.
