This is a question that I have personally asked and researched. It seems that if we eat of its flesh it should be a meat.
It remains under debate, without clear approval from either side of the arguement.
My personal research reveals this:
meat is from a mammal
fish is not a mammal.......yet it provides the protein that we seek from flesh . The same proteins can be gotten from eggs, beans and nuts.
There is also an religous aspect, which I never cared to delve into.....
You, go, and figure out the world and its collective thinking. I have been unsucessful!