Fish

denotes "a fish," Mat 7:10, Mar 6:38, etc.; apart from the Gospels, only in 1Co 15:39.

is a diminutive of No. 1, "a little fish," Mat 15:34, Mar 8:7.

is a diminutive of opson, "cooked meat," or "a relish, a dainty dish, especially of fish;" it denotes "a little fish," Joh 6:9, Joh 6:11, Joh 1:21-10, Joh 21:13.