The question that has plagued many a fish fryer is whether or not to reuse oil after frying fish. The answer, in short, is no. Fish oils are high in polyunsaturated fats and can oxidize when exposed to air for too long. 

What Happens When You Reuse Oil That Has Been Used for Fish?

Oils have a limited lifespan, regardless of whether they are used to fry fish or any other type of food. The oils that contain more polyunsaturated fatty acids break down more quickly than those with less polyunsaturated fats. 

Fish oils have a high concentration of polyunsaturated fat which means their life span is shorter than your average oil. This exposed oil will need to be changed at a much higher frequency than other frying oils.

Although the first time a cooking oil has been used should be considered the first and only time you can use it for frying, there are some exceptions depending on the type of cooking you do after frying food in it. 

If you fry something that is not fatty or oily, you have gotten the chance to reuse your cooking oil. This could include things like french fries, for example.

Frying foods high in fat content causes the oil to change once more. Ingredients with higher fat content are more likely to cause oils to become rancid quicker than they would when used for frying less fatty foods.

It doesn't matter how many times you use your fryer's oil after cooking fish because eventually it will all break down and be dangerous to eat. However, the rate at which that breakdown occurs depends on whether or not you cook other types of food in that same batch of oil before it goes bad.

Why You Should Avoid Using Oil That Has Been Used For Frying Fish

The smoking point of an oil is also another important aspect of using cooking oils properly and safely. The smoking point represents the temperature at which the fat molecules in the oil begin to break down into something that isn't safe for consumption. 

You should never allow an oil's temperature to exceed its smoking point because doing so leads to the creation of free radicals, which can be very dangerous for you to consume. When your oil reaches its smoking point, it should immediately be removed from heat and used at a temperature lower than this maximum temperature.

What Should You Do Instead of Reusing Oil That has Been Used for Frying Fish?

There are so many things you could do with old frying oil instead of reusing it. There are some good uses for worn-out oils. The only limit is your imagination so long as you avoid using cooking oils that have been used to cook fish or any other type of seafood product. If your cooking oil smells like seafood when it is cool, there is a chance that bacteria have had time to start growing in it while the fryer was hot.

You could experiment with making biodiesel, or even feed it to animals such as chickens when you want them to grow larger and more quickly. There are many things that can be done with old frying oil that will not only save you money but maintain a safe and healthy environment for everyone in your home.

Which Oil Is Best For Reheating? 

You should not use vegetable oils for reheating food because they can go rancid and produce harmful chemicals like free radicals. If you need to reheat your food, try using butter or olive oil instead.

With all this said, you should now know whether or not it is safe to reuse cooking oils that have been used for frying fish at least once before without altering their safety and quality (though there are other uses you could make of such old cooking oils). 

If you decide to reuse the fish oil to make something, be sure to stir the oil every few minutes while it's on the stove so that solids sink to the bottom and don't burn and give your oil a foul flavor and odor. Strain and then store it for further use. 

Some people claim it's okay to reuse cooking oil, I don't recommend it. There are many different oils that are better for frying fish because they won't break down as fast.

Therefore, the simple answer to the question of whether it is a good idea to reuse your cooking oil after you deep fry fish is, no - discard your oil and definitely don't use it again to fry any other type of food. You might also want to consider buying a separate deep fryer or pot specifically designated for cooking seafood because there are so many health concerns related to the improper disposal of greasy substances used in cooking seafood. 

What Is The Best Oil To Deep Fry Fish? 

Peanut oil is one of the best oils for deep frying fish, especially if you want a crispy crust on it without tasting too much of the frying process itself. Peanut oil has a relatively high smoke point making it ideal for deep frying foods for extended periods of time at high temperatures without degrading its quality or flavor profile. Safflower oil, and sunflower oil are also perfect for frying seafood.