All the recipes etc seem to call for fish fillets etc, not a whole fish (yes, scaled and gutted). Any guidelines for this?
Most recipes for proteins are based on thickness. Normally fish filets are about an inch thick. I would measure your fish at the widest part and adjust the time proportional to the thickness. For example if a salmon filet recipe calls for 1 hour for a 1 inch piece and your fish is 3 inches I would multiply the suggested time by 3.
I’ve not cooked whole fish because it has some considerable complexities. As in conventional cooking, the species of fish often determines the degree of doneness. Besides, i just prefer a nice quick fillet although 118F x 25 min. salmon tails can be delicious too. I like a 1" halibut too, 110F x 40 min. - to an hour if it’s a little thicker.
You don’t say specifically what kind of fish you are considering and what degree of doneness you are aiming for, so you give us quite a puzzle. Are you considering, trout, snapper, grouper, or shark?
Be careful with SV cooking times. Heat penetration is not linear. See Baldwin’s table 3.1 for fish cooking times and you will see what i mean.
Also note Baldwin’s comments on Pasteurization of fish. You should know well the source of your fish for your protection. Cooking whole fish makes it difficult to check for worms and other parasites.