Fish are very well attune to its surroundings and farm raised are good in themselves but you have to feed them something. Thats where the problem comes in. Recently a warning went out on a certain farm raised fish that were contaminted with pcbs.
Yes, this is still a problem in the US besides overfishing in all fish. They were fed ground up baitfish that "contained" traces of pcbs. Many rivers and tributarys still are being leeched in from old plants and dumped batteries from the past
If you eat fish caught out of a river or lake check your local fish advisory's as to how much you may consume on a given calender week. Some streams have a strict catch and release rule. You should always follow these guidelines. Acceptable consumtions must be followed ,as well as, fishing rules.
If you are close to a regular fishing area, that you eat fish from, try taking a ph test with a simple kit from a pet store. You will be surprised at the acid levels and also how people treat water in general. Sad but true.
Sorry to rant on TL, Im with you on this fight also!