Giraffe cats fall under the family Auchenoglanididae which in turn has three main sub families which to some extent all contain fish that get called giraffe cats.
These three sub families,
Notoglanidium, contains N.macrostoma which is known as the dwarf giraffe catfish and only reaches 10”
Parauchenoglanis, contains a number of fish of recognisable giraffe cat shape and pattern which strangely are in the main not commonly known as giraffe cats, all but P.punctatus, the spotted giraffe cat which can reach around 16”
The more usually encountered and mentioned giraffe cats, the larger ones, fall under the sub family Auchenoglanis and range from around 1’ to 3’ in size depending on the species.
thebiggerthebetter
has created a good write up on the different types, sizes, patterns within Auchenoglanis from his experiences and those of others.