Royal Gramma
Gramma loreto

Identification: Its coloration is deep magenta on the front half of the fish, and dark orange on the back half of the fish, with a small stripe running through the eye and a spot on the dorsal fin. 

Maximum Length: Attains a length of approximately 5 inches.

Origin: Caribbean, Tropical Western Atlantic, Red Sea

Minimum tank size:  20 Gallon

Behavior: Most fairy basslets, of which G. loreto is an example, live in more shaded areas and avoid strong lighting. They will, however, find their own hiding/shady places and areas in tanks over which metal halide lighting is used when they need them. The Royal Gramma makes an excellent fish for the beginner aquarist because it will readily accept a variety of prepared foods and usually does not take very long to acclimate to the aquarium environment. This species can behave aggressively towards other smaller passive fish and towards its own kind, but generally will remain relatively peaceful. This species may be kept in pairs so long as the aquarium is of good size. 

If is often said that no two Gramma loreto or Royal Gramma fish can be kept together. This is only a "partial truth".
If you buy two, three or even four of these fish and place them separately and at different times in the tank, they will fight for territory and a rather large tank will be needed for even two let alone four of these fish to be comfortable with each other.
German Hobbyists have managed to keep several of these fish together without the proverbial territorial fights, the ensuing raggedy fins as well as the demise of one or more of these beautiful fishes by simply purchasing several at the same time, acclimating them together, switching off the tank lights and introducing all of them into the aquarium as a group at one time.

(NOTE: If you buy only two and do so at different times, and the two fish happen to be of opposite sexes no fighting will occur either. The inherent problem with this is that you cannot tell what you are buying: there are no exterior signs of male or female nature visible at all to the buyer/hobbyist.)

Feeding and diet:  Meaty foods, including marine fish, crustaceans flesh, mysis shrimp and frozen preparations.

Reef Compatibility: Excellent