Got Your Fish?
The dolphin pin is given to trainees-submariners after they complete their training phase. However, not many are aware that the item isn’t actually referred to as a dolphin but rather a fish. The informal insignia for the submarine force is called “fish.”
After completing their basic training and receiving their fish, the double letter “s” is added to indicate that they are now a submarine specialist. The insignia of the submarine force is a submarine flanked by two dolphins, which honestly look more like fish than mammals.