Definitions:
a limbless cold-blooded vertebrate animal with gills and fins living wholly in water

a person who is strange in a specified way

catch or try to catch fish, typically by using a net or hook and line

search by groping or feeling for something concealed

a flat plate that is fixed on a beam or across a joint in order to give additional strength.

mend or strengthen with a fish.

join (rails in a railway track) with a fishplate.