This alien species is know as Skejg. Little is known of them. They are believed to be sentient, "fly" with monomolecular flagellas originating from their "fins" and they are able to cloak themselves, beeing almost invisible unless you use infrared devices or you have ears that are capableof hearing their high frequency sounds.

Fun fact: They were origninaly used in a comic I made almost a decade ago about an anthropoorphic pentagramm and they are STILL loosly based upon Muddy Mudskipper from Ren&Stimpy o.O