I have one for a while now and loving it. It's my most fav fish, BUT even my LFS
is saying that I got lucky that he is still alive. I bought him at my LFS
and he is the only one that survived from the entire shipment that they have sold. He/She wasnt an ORA but is willing to eat brine shrimp so therefore I am having a small tank on the side to keep that one fish fed... it is possible, but you have to be willing to jump through hoops to get there.
My new build is gonna have a fancy Refugium build just for growing pods
so I can make my little dragon happy
I doubt a 20g tall tank is the right choice though unless you are planning on more than enough LR
... and the tank needs to be well established. Run the tank for a yr and than maybe consider a mand. goby
Also, a cleaner shrimp and a goby do well together, so no problems there