Barracudas are fish that are fast and eat shiny things. They tried to eat the Vegimals' garden tools when they were planting mangrove tree seeds. But they didn't manage to do it because of the larger Octonauts. Several times the Vegimals and the Octonauts has to retreat into the dense mangrove forest to escape being bitten by one of the barracudas.
A Barracuda is a fish that looks like a thin and small shark.