Rainbow (herotilapia multispinosa) was my first guess, based mainly on the body shape and the dorsal and tail fins; looks like several others agree
colors are very dark for a Rainbow, but they do get that way when stressed . . . it's a nice fish, gets along well with others . . . won't cause trouble, and won't be troubled by others (generally)
colors are very dark for a Rainbow, but they do get that way when stressed . . . it's a nice fish, gets along well with others . . . won't cause trouble, and won't be troubled by others (generally)