I have to agree with everyone else. you definately need to get rid of the iradescants. As far as the bala goes though, How long are we talking here untill you get the 55 gallon? Despite what many people say/think. A bala shark (when still a baby) can do well in a smaller tank. (as long as it is not already skiddish and freaking out.) I grew two of mine out in a 30 gallon along with 2 chinese algae eaters, convict cichlid, and 3 clowns. When they reached around 6 inches each I bought the 55 gallon and moved them. Now I have one at 8 inches and 2 at 2 inches in my 55 gallon.
IMO if its only a month or two.....you can keep your bala as long as your ABSOLUTELY POSITIVE that you are getting the 55 gallon.
cringes in anticipation of the yelling that is about to come