what do you feed it

THANKS if your tank is 422 gallons u may be alright for a while but the adults will fight over territory especialy males. I have to get rid of one of the males in this post because the fights are becoming to frequent and more violent.Hi Sharptoothbass, your gobies are awesome!
I need your advise, I got 1 tank (422) keeping 2 marble gobies of size 8-9". Another FGT (422) keeping 3 marble gobies of size 12". Will they fight if I put the 2 8" marble gobies into the FGT with the bigger fish? Cos I am trying to free up 1 tank to rear juvenile monster fish. Not sure will the smaller gobies become victims?