recently got a 4 inch GATF and its currently kept with my micropeltes of the same size in a 1200 litre tank , its been one day and its not eating i wonder how long should i starve it ?
Don't try to starve him until he gets a little bit bigger. At this size they have very active metabolisms and it's not good for them to starve. I would recommend waiting until he's about six inches and has a little girth to starve him. Keep feeders constantly stocked until he's big enough to go through the starve.
I am very concerned that your baby GATF will end up as a feeder for your snakehead.