What kind of fish is this, caught in Cape Coral, Florida?
It looks like the spotfin jawfish, Opistognathus robinsi. The larger ocellated spot on the foredorsal fin is a key identifier for this species. They are not so common in Florida, but do inhabit sandy bottoms, such as canals. Are you sure about the length? It looks about 5 inches from the photo provided, when compared with the the size of the hole on the dock. This species grows to about 5 to 6 inches.

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