A term used in some regions to refer to a small fish.
El escañuelo nadaba alegremente entre las rocas del río.
The minnow swam happily among the rocks of the river.
El escañuelo nadaba alegremente en el estanque, ajeno a los peligros que lo rodeaban.
The minnow swam happily in the pond, oblivious to the dangers around it.