Noun | 1. | ![]() fish family - any of various families of fish order Perciformes, order Percomorphi, Perciformes, Percomorphi - one of the largest natural groups of fishes of both marine and fresh water: true perches; basses; tuna threadfin - mullet-like tropical marine fishes having pectoral fins with long threadlike rays genus Polydactylus, Polydactylus - a genus of Polynemidae |