IMO the clown fish are the best starter fish: extremely hardy, attractive, swim around actively, and aren't overly aggressive.
Out of all the fish I had, only one fish (my clown fish) survived when I went on vacation and my tank got cooked by the hot California summer
. It even survived the aftermath of decay which it had to go through while I was away. Clown fish are definitely extremely hardy.
I have always wondered though, is it possible to keep two clown fish together if they aren't a mated pair and one is introduced later on?