The fourth book in the New York Times bestselling Rainbow Fish series. It's Rainbow Fish's most challenging adventure yet, for he must brave the Sea Monsters' Cave, rumored to be the most dangerous place in the ocean, to find healing algae to cure the ailing bumpy-backed fish. Warned by his friends about the dreadful denizens of the deep--the giant rock monsters, the five-eyed globe fish, and the horrible creature with a thousand...