Striped eeltail catfish (Plotosus lineatus) can be found in brackish waters, lagoons, and coastal reefs. They frantically sift through the sand looking for crabs and small fish to eat. The spines on their dorsal fins are covered in a toxic mucus that can be painful, and even fatal to humans. We saw this crazy ball of fish in Lembeh, Indonesia. Read more in our post, Scuba Diving the Weird and Wonderful Waters of Lembeh Indonesia.