ponyfish of the family Leiognathidae, are small fish of the Indo-Pacific which often shoal in estuaries and enter fresh water. In life they are coated with slime and on death exude mucus, unattractive characteristics which have earned them the names of ‘slimy’ or ‘soapy’ in S. Africa. A more attractive alternative name, ‘silver-belly’, is self-explanatory.
Ponyfish have a very protractile mouth, a phenomenon which can be demonstrated by squeezing the head, when the mouth will shoot forward. For this reason they are also called ‘slipmouth’.