Jellyfish are not fish, their proper name is Jellies

As jellyfish are not vertebrates, let alone true fish, the word jellyfish is considered by some to be a misnomer. Public aquariums may use the terms jellies or sea jellies instead.[8] Indeed, it may be said that the term "jellies" has become more popular than "jellyfish".[1] In scientific literature, "jelly" and "jellyfish" are often used interchangeably.[9] Some sources may use the term "jelly" to refer to organisms in this taxon, as "jellyfish" may be considered inappropriate.[10] @Curionic

#staycurious

Source