Fisherman:
Therefore only God can produce a miracle
In addition to the fact that your premises don’t support your conclusion that only God can perform miracles, I should have added that your premises also don’t support the conclusion that God can perform miracles, or that supernatural entities can necessarily perform miracles, or that performing miracles is possible.
Also, the assertion that supernatural entities exist at all is unverifiable, and the term has no meaningful definition.
You might as well say something like:
Invisible goblins are supernatural and undetectable. Invisible goblins like Fisherman’s socks. Therefore if Fisherman can’t find his socks, invisible goblins took them.