Before you give any wild caught raw meat, it's best to freeze it for 3 or 4 weeks first to kill off any potential parasites.
Also with fish, some are more beneficial than others. I would not feed fish that are known for being high in mercury content, like Tuna, shark etc. The healthiest fish are low in mercury and high in omega fatty acids, so ideally salmon, rainbow trout, mackeral, smelt, sardines, anchovies. Fish like tilapia, cod and catfish are fine, but so low in oils and fatty acids that they're more of a filler meat.
When I feed fish, I usually choose smelt or sardines since they're most readily available and most expensive, and I do feed them whole.
I've attached a chart that has info on mercury levels and omega.
Oh one other thing, if you live in the pacific northwest, do NOT feed the salmon raw. They often carry a parasite that results in salmon poisoning disease. It's very serious and can kill dogs. The parasite can infect any fish in the salmon family.
Are you feeding a raw diet? My spaniel's on a raw diet, he gets a small whole mackerel once a week. I have the butcher gut them and cut off the tail but leave the head. Gutting is for my squeamishness, not the dog's.
I'm not sure of the origin of the fish (it's an Asian market) but I did see some larger mackerel that look just like some I saw when I was researching so I think I'll get those next time and cut them in half for portioning.
The only fish that is going to be of benefit is wild caught oily types. the benefits come from the oils for omegas. Farmed fish don't have near the benefits. The only thing is, be sure it isn't wild caught from the Pacific Northwest. Feeding those will be a risk of salmon poisoning which is fatal if fed raw to dogs. It would need to be wild caught from somewhere like the Atlantic.
And, you don't have to debone, but I would open them up and gut them to be sure there are no swallowed hooks.
I personally just give fish oil rather than fish, because I just don't have access to quality oily fish here. the oil is where the benefits come from, so its just easier for me to give the oil capsules instead.
Yes, oily fish is best. But even white fish is good for protein and variety. I wouldn't discount it because it isn't an oily fish. For fish I feed mostly mackerel, salmon, sardines and bluefish. But I will also feed tilapia, whiting and most any other type when I find it for a good price.
There are too many other proteins out there to feed rather than lower quality, non oily fish. the oils are the whole reason for feeding fish. otherwise, I would rather feed actual meat proteins that they will get considerably more nutrition out of. If I am given non oily fish for free, I will take it and feed it just for something a little different, but I wouldn't go out and buy it. It just isn't worth it nutritionally. Tialpia is almost nutritionless and non oily. If it's farm raised, it is nutritionless.
Fish in general really isn't a natural part of their diet. In the wild, they are eating wild game red meats which already have all the omegas 3's needed naturally. We supplement our dogs with fish oils and oily fish because most of us aren't lucky enough(or financialy able) to be able to feed only grass fed red meats to supply those omegas. If you could feed grass fed only red meats daily (no grain ever fed at all) like beef, lamb, pork, goat, deer, elk etc.....you wouldn't have to give any omega supplement.
My dogs love fish too much not to give it to them. So I do, oily fish more often than other fish. But since they like it I see no reason not to give it to them when I find it for a good price. Maybe your luckier than I am and can get a big variety of meats. But one great thing about raw is that you can easily tailor it to your animals needs and your availability.
If they love it, and you can get quality oily types there isn't anything wrong with feeding it several times a week. If it's wild caught you are getting the needed omegas that way and no need to supplement. If it's farmed, you aren't getting the omega oils that are needed and you will need to supplement. Feeding it is fine, but I wouldn't make it the diet staple. If your dogs are eating it, it won't hurt still a few times a week. Something different for sure.
The only fish I have access to is catfish. Mostly farmed which I won't buy. ZERO nutritional quality even out of the river. If I get it free, I just add it with another protein of some sort.