Indeed! They are different species, but very close relatives. Marbeled sleepers (not a true goby, but closely related) have the latin name of Oxyeleotris marmorata and watercows are Eleotris vittata. Those latin names could be outdated as this family of fish is constantly being scientifically revised... but, at least at one time they had these latin names.guppy said:Close relative, this one has a more uniform coloration and a more tapered body.