User blog comment:Kogath/Monster Hunter: World Discussion/@comment-31029678-20180125192955/@comment-26034899-20180125200803

There's nothing wyvern-like about the Gajaus, and since they were classified as Fish in Tri and 3U under the label of Catfish, it's pretty likely that they will be listed as Fish. Then again, Delex are classified as Piscine Wyverns despite not being very wyvern-like, so it's anyone's guess.