I would probably not try to do this with ACF. There are a lot of wholesale plugins for WooCommerce available that lets you do these things, like bulk discounts. I’d look there first.
After you got that working you can figure out how to make it as easy as possible to change the daily prices. There are plugins for bulk editing, where you can manage the prices for several products in one screen.
I would not make the fish a variable product, instead make a separate product for each fish type.
Hope that helps.
