Originally Posted by browniebuck
Considering what you have in the tank, I would say that you could get away with more than one more fish. I know that my tank is probably overstocked (though everything in the tank has been doing very well for over 6 months), but my 55 has an eibli angel, a keyhole angel (they get along just fine), 4 blue green chromis, a green mandarin, a maroon clown, a foxface (he will be traded in by the end of the year, as he is getting too big), and a yellow tailed damsel. I wouldn't suggest going with that large of a bioload, but I am just saying that 3 fish isn't, by any means, your limit.
With that being said, in order to keep these fish happy I am constantly adding top off water, doing water changes maybe every month or so (and according to the tests that I run, I really don't need to do them that often, just do because I feel like I should), and checking the tank and its inhabitants daily for any signs of problems. I think that it also depends on how much LR/LS you have in the tank to add to the filtration, as well as having various inverts there to help clean things up. I have nearly 100LBS of LR in my tank that was fully cured and FULL of critters when I got it (if you look at my rock for any period of time, you will see tons of pods, some nearly as big as a dime).
So, I guess that depending on your system/filtration, you could get away with adding more than others say (especially if they are smaller fish).
I would agree that this may be a bit overstocked, although certain scenarios will allow for a higher bio-load as noted (fltration, etc). I'm sure most people definitely won't recommend it for those that are new to the hobby since so much can go so wrong so quickly.
I would say that 6 or 7 fish is your max, assuming they're all smaller fish (smaller being their size as a full grown adult). The larger the fish will get when fullgrown, the less you want in your tank. So for instance, if you decide to get a Fairy Wrasse that can get up to 6-8 inches, you probably don't want to do more than 5 fish total, however if you do a few blue/green chromis then you could probably do 6 or 7. Just something to keep in mind. Hope that helps.