Check out this mesmerizing school of striped eel catfish (Plotosus lineatus), captured by Abyss Dive Center Bali.

When young they form large ball-shaped schools of up to a 100 fish, but as they mature, they prefer to be alone or in smaller groups. On their first dorsal and each of their pectoral fins they have venomous spines to protect them from predators. Once mature, the venom can be fatal to humans!