http://65.66.134.201/cgi-bin/webster/webster.exe?search_for_texts_web1828=fish
"FISH, n. [L. piscis.]
1. An animal that lives in water. Fish is a general name for a class of animals subsisting in water, which were distributed by Linne into six orders. They breathe by means of gills, swim by the aid of fins, and are oviparous. Some of them have the skeleton bony, and others cartilaginous. Most of the former have the opening of the gills closed by a peculiar covering, called the gill-lid; many of the latter have no gill-lid, and are hence said to breathe through apertures. Cetaceous animals, as the whale and dolphin, are, in popular language, called fishes, and have been so classed by some naturalists; but they breathe by lungs, and are viviparous, like quadrupeds. The term fish has been also extended to other aquatic animals, such as shell-fish, lobsters, &c. We use fish, in the singular, for fishes in general or the whole race."
He actually quoted that entire definition already. Somehow, he thought it helped his case...