all fishes are ok eat it in a clean hygienic restaurant, or buy it in shop cook by yourself. same goes for all meats and chicken.

River fish not only taste like crap, but they are caught in highly polluted rivers and are chalk full of heavy metals and toxins.

Stick with the ocean fish if you can.

Each person has his own pet theory, and of course, apprehensions.  I have seen how many industrial plants discharge directly their industrial wastes into rivers, lakes, streams, reservoirs, etc.  I also see many cities doing exactly the same with their wastes.  So, it would be a safe guess to assume that that type of water is probably more polluted than either the East or South China Seas.  At least away from shoreline.

So, I have always thought that whatever fish, shrimp, etc caught in non-saline waters within China will have a high probability of a higher than normal heavy metals or other type of pollutants within them.  And for that reason, I do refrain from eating them, at home and at restaurants too.

Yet, if I see at the market a fish that I do know can only be caught at the sea, like for example a red snapper, I would buy it and cook it and eat it without a second thought.

But that is me, and I do respect what others may think or do.

My GF has a good friend who owns a 1,000 mu farm not too far away.  He grows sugar cane, and uses no pesticides nor fertilizers.  Within the farm, there are a few irrigation ponds to store water, and he also uses them to grow fish and shrimp.  There, I have no problem to go and fish, and eat what I caught, because I have tested the water a few times, and it is potable.  The ponds are fed from a nearby spring, and they have interconnecting channels to carry water to all.