Yes they can eat whole fish.

Don't feed raw and kibble at the same time. Raw takes about 5 hours to digest compared to 15 for kibble, and you don't want raw getting "stuck" behind the kibble because it can cause digestive upset. You can feed raw in the morning and kibble at night, or vice versa.

Just be aware that fish can be kind of hard on their tummies at first, so loose stool will be normal until they adjust. Some dogs can't handle much fish. I would feed the fish alone at first so not to overwhelm their system.

Good luck!