Under the cover of night, the Mysids can be found. As a favourite snack of most fish, these crustaceans hide until it's safe to come out: after dark! Christian and Sayat are on Lake Ontario with the Department of Fisheries and Oceans in search of the invisible critter. This mission is not for the faint of heart: it uses heavy machinery, it's cold, dark and wet - but Leo's FishHeads are up to the challenge!