Ghiozzo is a carnivorous fish-based B.O.W. introduced in Resident Evil: Revelations. In Italian, Ghiozzo translates into Goby, an actual breed of fish.
In a video shown by Il Veltro leader Jack Norman to the BSAA, he demonstrated the frightening power of the T-Abyss Virus by injecting it into a small aquarium filled with a group of Arowana. The Arowana soon mutated into a flock of vicious Ghiozzos.
Later on the Queen Zenobia, Jill Valentine and Parker Luciani are investigating a casino. They found a fountain with fish in it (the same breed as the ones experimented by Norman), and accidentally released T-Abyss virus into the fountain, immediately transforming the fish into Ghiozzos.