So how do you defrost your fish!? One important rule!
Never defrost under room temperature or using warm water!
Reasons are you are letting bacteria to grow on your fish rapidly and it does not taste good because the difference between freezing and room temperature/warm water is big enough to cause the fish meat texture and taste to turn bad.
So how should I defrost it?
Simply move from Freezer to 'Fresh Area' of fridge
If you freeze your fish in the freezer and your fish comes with packaging, don't remove the packaging, just move it to the “Fresh Area” of the fridge until it fully defrosts.
Leave it overnight
How long does it take to defrost? Just take out the fish and put it in the “Fresh Area” the night before you cook. This method always works! Simple! Also, remember to put your fish away from any ready-to-eat foods for the best hygiene practice.
Alternative
Another quicker and well known method of defrosting fish is put it in cold water. But ! the fish must be with sealed bag or somehow don’t let it in contact with water because moisture leads to less flavor and not easy to cook. That’s why youtube chefs dry fish and fish fillet with paper towels or towels. Leave the fish in cold water until it fully defrost. You can gently press the flesh to see if it still feel frozen. The time needed is very much depends on size of your fish.
Lastly
Don't try microwave, my experience tells me it doesn't taste better than the normal way. It may due to the sporadic heat of the microwave and the dramatic temperature change that shocks the fish meat and mess with its texture. Defrosting through refrigerator is always the first choice.
References:
https://freshfromthefreezer.co.uk/faqs/defrosting-meat-fish/defrosting-fish/
https://www.bonappetit.com/story/how-to-safely-thaw-frozen-fish