Last week I bought some fresh cod from the market, as my fridge doesn't have a lightbulb inside, I discovered that the fish was glowing a greenish blue colour through it's wrapping! Knowing that I live 20km from a nuclear ower plant I got a bit scared and threw the fish away. How could this fish be contaminated?
It's quite unlikely that the glowing was due to radiation, if it was radioactive enough to glow like that you would probably get serious radiation poisoning just from being near it, and the fish would have been unlikely to live for long enough to get to catchworthy size. It's more likely that there were algae in the fish which phosphoresce, or there are other microorganisms which can glow in the same way, by taking energy in as one form and emitting it as light.