can you tell how big a fish is on your depth finder? if so how? i see big arches from time to time and fish for them and catch small fish. i also found a spot last year that had some huge arches. fished for them several times and know several other folks that fished them same acrhes and nothing. i tried diffrent baits and found out what i think was gar. hard scales make nice arches. i fish santee and find areas where i mark plenty of fish and catch fish but never really mark any big fish and go back at night and catch big fish but still dont really mark big fish. seems like sometimes i mark big fish and catch big fish. then other times i catch big fish where i dont mark hardly any big fish. i referring to fish from 5lbs to 50lbs. also does a fish on a hard bottom mark differnt than a soft bottom?