Yes, but normally they grow back slowly. However, if fin rot has reached the base of the fin, then the goldfish would be in pain the rest of its life.
The fin on the back of an orca is called the dorsal fin.
The dorsal fin is the fin on the back of a fish, for example the typical triangular fin on the back of a shark is its dorsal fin.
Blotches on the dorsal fin and tail fin(s) can be the diseases fin and tail rot, easily cured with medication.
No, a dorsal fin from a fish is on its back area.
Dorsal fin
The fin on the top/back of all fish is called the "Dorsal Fin."
Some sharks have a second dorsal fin, it's between the main dorsal fin in the middle of the back, and the tail. Not all fish have a second dorsal fin.
The tail fins are 'flukes'. Otherwise the fin on any marine animal is "... fin" where "..,." is the adjective denoting its position on the body.
The dorsal fin is located on the top of a fish's body, along its back. It helps with stability and maneuvering in the water.
the dorsal fin
A dorsal fin is the one on the top of the fishes back.