What model of FATSHARK you got now?
If you have latest FATSHARK circa 2016 and above all "FPV" camera with 5.8ghz video transmission works well with FATSHARK just make sure to tune it to correct video channel. Just go to banggood.com and search "FPV camera" you'll pretty much good to go. But first i need to know which fatshark module you're using? I'm still using 10 year old 8ch FPV goggle running great with any camera on my planes and trucks.