The term FROG-EATING FISH can be summarized as a fish that eats frogs, and the crossword solution for this term is EEL, which is a three-letter word. Eels are a type of fish that are found in both freshwater and saltwater habitats. They have long, snake-like bodies and are carnivorous, meaning they feed on other animals. Some species of EEL are known to eat frogs, making them an example of a frog-eating fish.