Those percs will outgrow that tank pretty quickly IMO. A tank that small you'd be better off going with a small goby.
I have a 7.5 gallon tank with a pygmy hawkfish and it grows algae like crazy. I do waterchanges on it weekly (almost need to do it twice a week). But the algae still grows. I'm thinking of removing the fish and putting a cleaner shrimp or something less maintenance in it.
Anyway, thats my two cents.
