what about a watchman goby? yellow watchman, randals goby and many more fun fish. The coral gobys are also very interesting. 6 lines are also great, however I have head since they eat the same things "pods" as a mandarin you can only have one or the other.
Have you thought about adding a
fuge? You could place it above the tank (pumping water up to it via a power head) and use gravity to pull the water back into your 29. It would help lower
nitrates and give pods a place to live and reproduce increasing your chances of having a happy mandarin. A small acryllic tank would be easiest, if you decide to get a
fuge keep the turnover through it slow. You may also want to look into a tube
fuge TR EP88, a great idea, I just built one.
