Ive got 2 that im trying to mate.
First off, What size is your tank, how old is it and which spieces are we refering too?
Gobiodon histrio
or
Gobiodon erythrospilus
Mine are histrio
Smaller is better to start with these guys.
They are pod eaters so they will generally eat pods until they have decimated the population.
My first one started in a 3.5 gal went for about 2 weeks without touching any prepaired foods.
After he finished with the pods and he was actually hungry. I got him to start takeing frozen brine by using a pipet and making the shrimp wiggle in and out of the end right in front of his face, Once he got use to taking frozen he pretty much adapted to prepaired foods without a problem.
My second one started in a 10 Gal its very young and while it fed off pods for the first few days,
It quickley learned by example from my 1st.
They now live off my mix off brine, garlic, Mysis flake, Veg flake, and cyclopeeze. But will take flake if i dont have any mix made up. Small feedings once in the morning and once at nite.
I also noticed that because they are a pod grazer, They dont eat all at once and need a little time between each bite.
There natural habitat it in the branch's of acropora coral, Even a skeleton of one will help them feel more comfortable and help ease there transiton to tank life.