Cetis are one of many background characters in the original Galaxy on Fire. These green beings have green skin and mandibles, and sometimes a blue space suit. Cetis and Greys are the only two known species to have only one name. Although there are two distinct "types" of Ceti, it's unknown if they represent different genders of the species.
Not much is known about this species at all.
The fate of Cetis is unknown as they are not found in GOF2.