I picked up a used 15 gallon tank a couple weeks ago. The tank came with a group of 7 neon tetras, a couple snails and couple guppies. All the fish looked good except this one Neon that was missing it's tail. It was having trouble getting food because the other fish were faster. I moved it into a tank by itself so that I could make sure it was getting food. It has been eating but after a couple weeks I don't see any sign it's tail is healing. Will it grow back or is it stuck this way?