Zoology/Fish that swim
I was eating a piece of boneless salmon when I had this question. Boneless salmon can swim and so can salmon with bones in them.Why aren't they all boneless? Do boneless fish swim less efficiently than fish with bones? It seems to me that the opposite would be true.
I hope that you are not pulling my leg but the only fish without bones are the fishes like sharks and rays which have skeletons of cartilage. Your salmon was processed and the bones removed. You asked why all fishes are not boneless. Because they could not survive