Mummichog from a Narragansett term which means "going in crowds", which reflects the mummichog's strong shoaling tendency. Colloquial names include mummy, killie, salt water minnow, mud minnow, mud dabbler, marsh minnow, brackish water chub, gudgeon, and common killifish. Some of these terms may lead to confusion: the term minnow should be reserved for species of the family Cyprinidae, the mudminnows are members of the family Umbridae, and the name gudgeon is used for various bottom-dwelling species of cyprinid, eleotrid, and ptereleotrid fishes, none of which belongs to the same family as the fundulid mummichog. The body of the mummichog is elongate
Mummichog morphological differences. and genomic Further, eggs of the northern subspecies have filaments (adhesive chorionic fibrils) that eggs of the southern subspecies lack. While the northern subspecies deposits eggs in the sand, the southern subspecies often deposits eggs inside empty mussel shells. The mummichog is very similar to the banded killifish, "Fundulus diaphanus", and indeed the two species have been known to interbreed. The two species may overlap in their choice of habitat, but in general the banded killifish is more commonly found in freshwater, which is not the case for the mummichog. The banded killifish tends to have thin dark