Why for some fish you remove organs first when filleting why for some fish you don't?

In some fishes before filleting we remove the organs in some fishes we don't because as we don't know what the fish would have consumed before catching.

Explanation:

All the fishes before preparation should be scaled, gutted and cleaned. After scaling and gutting if you need to have a perfect fry or roast you need to fillet it in a proper way. Proper filleting is done from the tail towards the head.

It is important to remove the organs first as we don't know what the fish would have consumed before catching. The organs might be hazardous to our health and there are chances of parasites too. In some small fishes like Smelt it is not that necessary to remove the organs. Many people also love eating fishes with the organs.