What is "ponyfish"

n. Any of many fish of the family Leiognathidae; the slipmouths

The ponyfishes, also known as slipmouths or slimys / slimies, are a small family, Leiognathidae, of fishes in the order Perciformes. They inhabit marine and brackish waters in the Indian and West Pacific Oceans. They can be used in the preparation of bagoong.

Ponyfishes are small and laterally compressed in shape, with a bland, silvery colouration. They are distinguished by highly extensible mouths, and the presence of a mechanism for locking the spines in the dorsal and anal fins. They also possess a luminous organ in their throats, which projects light through the animal's underside.