Either the grease is too cold or the pot is overcrowded. The grease should boil when you drop in a piece of fish. But be careful you dont burn the oil. Not sure if my temp gauge is right or not, but I want my guage to read @ 300-310* when I start dropping in fillets. Once you put in enough to cover the top of the pot cook those before adding any more. You dont want fish stacked on top of fish in your fryer. If you need to be cooking more pieces than the pot will cook adequately then get a bigger pot.