My parents used to have a big saltwater fish tank. I do have to say that small clownfish (the dark kind & the lighter orange kind as well) are generally good choices, they are hardy little fish, and are known to survive very long.
The tank was very pretty to look at, but was a pain in the a*s to keep clean. Also, it is very hard to get the formulas with the salt and everything *just* right. And if the formula is not right, everything in the tank can die. We had problems with red algae everywhere, took over everything, the rocks, the coral, everything. And we went to a fish and reptile specialist, and everything we did didn't seem to get the red algae away. It seems you can prevent it, but not get rid of it.
Like I said, if the formula is not just right, everything in the tank will very likely die. Every fish we put in, died of unknown causes except for a small clownfish that survived for a whole year. (Keep in mind we were going to a fish/reptile specialist, and he would tell us what kinds of fish not to mix with other kinds of fish and everything.) And it was not the clownfish attacking the other fish, they would just die. (We would watch some of the deaths unfortunately, and they would just get scared and pass away, it was random.)
It's a very hard thing to get right, but the colorful fish are gorgeous to look at! And if you're doing saltwater, there are some beautiful fish out there, and very colorful! It was a hard setup for my family to do, but they are actually thinking of re considering and getting an even bigger tank again this time, and starting the process over! If you have a lot of free time to devote to it, it's worth a try!