What is cat phylum class order family genus and species?

You can find out the classification of most common organisms by looking it up in Wikipedia - the relevant information appears in a sidebar, to the right. In the case of a catfish, the corresponding information says: Kingdom: Animalia; Phylum: Chordata; Class: Actinopterygii; Superorder Ostariophysi; Order: Siluriformes.As to the genus and species, please note that there are several genera and species of catfish; that's why the Wikipedia sidebar ends with "Order" in this case.