I was interested in the scientific name... apparently a mormon is a female demon which eats children (nothing to do with the religious Mormons) and a derivative of that word, mormo-, means "mask", so the latter is probably the reason for the specific name (i.e. "masked"). The original description of this species does not give an etymology of the name.
@Chlidonias Interesting. For some reason I make a mental link between that and Murmillo, a type of gladiator in Roman times. While it isn't derived from the same word (though it might have been - the murmillo wore heavy, gilded helmets/masks) as I hoped it would be, I found out that it is in fact derived from the Greek word for the elephantnose fish (μόρμυλος - pronounced mormilos).
However, there may still be a link between the Mormo and mormilos.
Edit: Did a bit more research and mental dialogue and figured that the word for elephantnose fish could be derived from the hideous monster in some way... Probably not, but pleases me to think it might be
@amur leopard - the name for the mormyrids was simply transferred over from the Greek name for the Sea Bream (Sparus aurata) of the Mediterranean. It has nothing to do with monsters.
Regarding the gladiatorial murmillos, the etymology is uncertain although the fish connection is most accepted (although it is referring to Sparus, not mormyrids as many websites state). Supposedly there are rare helmets depicting fish on them to support this. Another suggestion is that the name comes from the same root as murex, due to the shield or helmet being likened to the shell (although I would imagine some connection to purple might be more likely in that regard).
