As long as he is eating frozen I say go for it! They are wonderful fish and apparently not really fast growers. Mine has been the same size for the 9 months I have had him and he is about 4 maybe 5 inches. Lots of personality and very active for the most part. As long as you feed them before doing anything in the tank they won't be interested in your hand and will probably just go find a place to sleep. I would get some sand eels and cut them so he can eat them and feed him that as well as some very small
raw shrimp as well. Sand eels are pretty skinny so he should be able to handle that.