Any green bonding wire will work. Attaching to a bonding wire connection will add protection to most under water hardware attached to the boat. If your goal is to add extra protection to the prop and shaft. You may want to check if this is achievable. Because of gears, bearings and a combinations of shafts in the reverse gear, grounding from the engine is not always achieved. Many times the prop anode is a stand alone and is not part of the bonding system unless a grounding brush is used on the shaft. There are times when all parts are making contact and the resistance level is less than 1 ohm and other times it is much greater or infinite. You normally want to see about .5 to .7 or less when checking for good continuity between bonded components. If you want to make sure that the fish is used for added protection for the prop and shaft. You would want to use a large alligator clip and attach the fish anode cable to the shaft coupling. The fish would be adding protection to the shaft and prop for sure.
The galvanic isolator is a good choice to help increase the anode longevity if you spend a lot of time in marinas using shore power.
