I recommend getting the gar off goldfish immediately. They gave my gar hole in head disease and its a pain to reverse and heal it (BTW: is almost completely healed up for my gars). Switch the red rosy minnows if you want to feed live or go to your local bait shop. If you can try and find a clean bait shop. My bait shop sells crappie minnows, muskey minnows and other types of minnows local to my area.
Starving is a good way to get them onto a new kind of food. Mine love frozen silversides, but at 11" it may be to small still to eat them. You could try cutting up shrimp and tilapia for him. Gars go hungry very very fast. Or atleast mine do. You can go no more than a week and im sure he will take just about anything. I didnt feed my gar for about 4 days and he was eating the small bloodworms i give my stingray.
In my opinion, a gar at 11" is harder to feed than when they get 15". Smaller mouth so its harder to get food for. As for pellets, mine didnt start eating pellets until they were at 16". One day i was just feeding my bass and one gar took the pellet and liked it. The other gar saw it and followed along. I evevn had them on flakes for about 3 weeks if you can believe that.
I agree with HungDang. As gar get older they become more chill and laid back, just kinda float there or lay at the bottom. They will snap at almost anything, including your fingers and hand so watch out. Mine are barely a year old and are just super chill fish.
Good luck with the gar and i hope you enjoy him as much as i enjoy my gar.
