A giant moray eel, Gymnothorax javanicus, stares out from his cave in the coral reef off the coast of Dar es Salaam. These eels grow up to up to three meters, the head can reach the size of a mans upper leg. If bitten by a giant moray eel, it is unlikely that you will ever forget it. Fortunately these eels are relatively shy and normally retreat into their hole at the sight of a diver.