I think if changes are to be made they should be

*Offhand = Net
*New Ability "Cast Net 1,2,3" each yielding more fish for a higher GP cost
*Narrow down the amount of fish that can be obtained at each fishing hole making better use of the Bait/Time of day/ Weather mechanic
*Fish Basket/Tackle Box inventory tab
*Mooch should allow you to use a fish from your inventory(GP Cost)
*Double Mooch should work like Mooch currently does
*Add more uses for fish I.E. Daily Supply Missions from the FSH Company, tournaments, recipes, Wall Trophies (House Item requiring 100 of that fish).