As mentioned, not even having 3 feet in length kills the possibility of even a Tomini Tang (smallest one available) in your tank. I wouldn't even put a Coral Beauty or Dwarf Angel in there as I feel they are best suited for a 4 foot long tank. That said a Pygmy Angel might work in a tank that size as they max out at 3 inches in length but need the space as they are very active. Examples of Pygmy Angels are the Cherubfish, Flameback Angel, Yellowtail, Fisher's and Multicolor. Of the bunch the Cherubfish is probably the one I would recommend the most. Flamebacks and Yellowtails tend to be fairly aggressive.