You shouldnt have gotten a mandarin. They live solely off of pods, he will slowly starve to death. Give it 3 months, and it will look like a skeleton. Especially since you have a banded pipe fish. They are all competing for the same food. You need to do more research befor you buy fish. Any body would have told you not to get a mandarin.
You have too many fish in a 14g tank. SW is basically, 1 inch per 5 gallons. With the damsel and pipefish, you allready have too many inches. Not to hate on you, just looking out for the fish