My tank is 14 months young & I have had just a pair of clown fish, a springer damsel, & a starry blenny in since the tank was ready to support life. I would like to add just one more fish but am concerned that it may cause a problem with the current occupants because they have been the only ones in the tank. It is a IM 25 gal lagoon. If you think I could get away with one more addition, I would love to hear some suggestions!