We had one I named Nemo (after finding Nemo, then I couln't tell the difference - "no, it has strips, it must be a Nemo fish").
He lived for 12.5 years, and grew about 20cm. We only had one though. Yes, he did sleep on his side, so many times we thought he was dead.
Seemed pretty hardy to me.. he survived many disease outbreaks. Yes, sure did clean up lots of fry. He loved to hide in his ship, and at dusk I would wait to see him come out, and he would swim, prance (like only a fish can) and spin in circles. I loved it.
Sadly, he died sometime late last year. We had had him since a little fry, only a cm long..