Doctors say we should eat more fish as it is good for our health. Let’s try to become professionals when it comes to fish, and make a gourmet trip to the supermarket.

#1 Chilled or frozen fish? shutterstock Chilled fish is fresh fish that is cooled down right after it is caught. You can find it on ice in supermarkets. In most cases, this fish is grown on fish farms.

Sometimes frozen fish can be sold as chilled. You’d better ask a seller where the fish was caught. If this place is far away from yours, there’s a high risk the fish was frozen first. Another thing that matters is the size of the fish. The bigger the fish is, the higher is the risk that it is full of hormones. In this case, it will do you no good.

#2 Frozen or fresh fish? shutterstock Actually, both types of fish are good for health. Fresh fish is a little bit tastier than frozen. Frozen fish can be deformed, as it was frozen right after it was caught. So, the form doesn’t influence the quality. To preserve all vitamins and nutrients in fish, cook it right after it is defrosted. However, if frozen fish are stuck together they were defrosted and then re-frozen once again. Keep it in mind when buying fish.

#3 A fish fillet or a whole fish? unsplash Public Domain Dedication About 20% of fish in supermarkets are fake. And practically in all cases, it is a fillet. Sometimes cheap fish can be sold instead of valuable one. Another important thing you should know, manufacturers can use chemicals to debone fish. To minimize risks, buy a whole fish. Choosing a fillet, buy the one with skin so you know whose fillet you are going to buy.

#4 Frost on the fish. Is it ok? shutterstock There shouldn't be much frost: no more than 5% of the fish weight. Sometimes manufacturers provide wrong information on the package. That is why you'd better check the fish by yourself. For example, if you see cracks in the ice it means that there is a lot of frost or the fish was defrosted several times. If the ice is yellow, it means this fish is not fresh.

#5 What information should be placed on the package? shutterstock To make the right choice, look for the following information on the pack: the contents (the product must contain only fish and water), and the place the fish was caught and packed. The last is very important for fillets. If there is a large distance between these places, it means fish was frozen, then unfrozen to make fillets and frozen once again.

#6 What chemical additives can be found in fish? shutterstock Have you ever been in a situation when you unfroze the fish and there is half the weight you've bought? The reason for that is polyphosphates which help to keep water in fish. Not all manufacturers provide this information. When you fry this fish in a pan it becomes foamy. Unfortunately, polyphosphates are not the only additives. Mercury can be found in fish that live in dirty waters. Biologically active amines, including the most dangerous - histamine- can be found as a result of improper storage or processing.