If you can't do the aquatic dinosaurs update then I suggest you just do Amphibious Dinosaurs like the Limnoscelis, Sarcosuchus, Koolasaurus, etc. I imagine those dinosaurs to have a specific need for the amount of water in their enclosure as well and that they will have their own fish feeder that can only be placed on water. I think the amphibious dinosaurs should be introduced on Isla Tacaño.