Catfish form part of the Order Siluriformes, which includes 24 freshwater families of catfish, and 1 coastal water family. This family, Plotosidae, is represented in Sydney by two species; the Striped Catfish and the Estuary Catfish.
The Estuary Catfish (Cnidoglanis Macrocephala) is a solitary fish which is rather large and usually hiding in overhangs. A stab from the fin spines is extremely painful and repeats can be fatal.