to keep any dragonet you need to have(recommended) a fuge. There has to be a safe spot for the pods to reproduce. Unless you have a larger tank with about 100+lbs of rock, it will be very difficult for the pods to reproduce. Get some cheato, some prebottled pods, and start a little fuge. You can do it with a tupperware bin even, it doesnt have to be fancy. You can also put a strawberry-type woven little basket upside down (like a little dome) in the tank and cover it with small peices of LR. The pods will be able to reproduce in the 'dome' and then crawl out safely when they are ready. Some people put some live rock and caulerpa in thier overflow box like a mini- in-tank fuge and the pods crawl out when they are ready. Some people suction a little 'soap dish' (clear plastic thing that holds bottles of shampoo etc. in the shower and has little holes in it) and fill it with cheato- right inside the display tank.
I think that you will be seeding your tank more like 1x/week rather than 1x/month if you dont have a little pod factory going. Try to train him to eat prepared foods but it isnt easy, and not all of them take well to it. remember that other fish like pods too, so if you have other fish, they will also help deplete the pod population.
i have a mandarin dragonet.. also in a tank about your size, mine is a 44g corner (tall). i only have him and a goby in the tank (as far as fish). I keep a out of tank fuge, and also a mini fuge in the overflow just for fun. The pods crawl out of the overflow and he pecs them right off the plastic. Mine also eats prepared food(thank god) so that helps ALOT.
Heres a pic of a pod. These are what you are looking for in your tank, or more specifically- on your glass- where it will be easy to spot them. the black area is a PENNY for size comparison. They are tiny little critters.