QDoes tritium become concentrated in fish? And will eating fish be dangerous?
ANo, tritium does not become concentrated in organisms.

For the most part, tritium exists as a liquid, and as with water, it is excreted from the body. Studies confirm that it does not accumulate or become concentrated within the body. If it enters the body as tritiated water, it is metabolized in around 10 days. If it bonds with an organic substance such as protein and enters the body as organically bound tritium, the majority is excreted in most cases in around 40 days, and any remaining tritium is eventually excreted later.