Most fish are colorblind, despite the opinion of many sportfishermen. Fish can see color shadings, reflected light, shape, and movement, which probably accounts for the acceptance or rejection of artificial lures used by fishermen.
Most kinds encountered by anglers are.
The latter are most often from tropical regions of both the Atlantic and Pacific Oceans. They cannot, without personal knowledge of the types of fish which are at times poisonous. Frequently local customs can be relied upon. For most species, truly fresh fish is almost odorless. Very little in most.