depending on the fish, but i would say that's dangerous. all those tiny little bones will choke a puppy.
i think boneless fillet would be okay. but it must be a really clean cut.
my boy gets cooked salmon every now and again. thoroughly cooked bones are soft and good source of minerals.
depends on the fish, we fed raw fish. the smaller ones I found were better , mackrel and sardines ect. the salmon I dont know where you live but here there is a risk of salmon poisoning, they say to freeze it a few days before feeding to kill the bacteria , we just never fed it wasn't worth it too us. Id rather feed raw then cooked though for risk with the bones.