This deep fried method of cooking fish is the most common technique used to make fish-n-chips.

This method involves cooking fish in a total submersion of fat. The fat is usually oils of canola, corn, cottonseed, peanut, pure olive, safflower, sunflower, or solid vegetable shortening. The choice of a good oil is up to you according to your taste. Peanut oil is very nice choice for deep frying fish.
Other
than a deep fryer, a
deep pan or wok can be used
It's important to maintain the cooking oil at the correct temperature. If the temp drops down below 350°, then the fish will begin to absorb the cooking oil and it will become greasy and soggy. If it rises above 375°, the fish will overcook on the outside without cooking the inside.
A deep frying thermometer is a great way to help maintain and adjust the temperature of the oil.
You can coat them in a breading or the batter of your choice. Dredging the fish in flour first can help the batter to stick.
Gently add just a few pieces at a time to the hot oil. Be sure not to overcrowd it because the temperature of the oil will drop when food is added to it.
Cook for a few minutes until they're done. They should be a nice golden brown on the outside, and moist and flaky on the inside. Drain for a few seconds in a fry basket, then place on paper towels to help soak up the excess oil.
If you'll be frying more fish, place the cooked fish in a warm oven at around 175°. Be sure to allow for the cooking oil to heat back up before adding another batch of fish.
Serve immediately with your favorite dipping sauce and sides. Enjoy!
