Avoid defrosting seafood directly in vacuum-sealed plastic packaging, as it can cause botulism, a rare but serious condition caused by a toxin called Clostridium botulinum.
Botulism thrives in places without oxygen, like inside a vacuum-sealed package. The risk increases when the fish reaches a temperature of 40 degrees F or higher while thawing.
Instead, remove the fish from the vacuum-sealed plastic packaging and place them in a reusable plastic bag, glass container, or on a plate or glass tray.
If all else fails, pierce holes or peel open the vacuum-sealed packaging and place it on a plate. Put it in a fridge at 40 degrees Fahrenheit or lower to defrost overnight.