The name eel tailed catfish is usually assosiated with catfish from the Tandus family which have species present in Tropical Asia and Australia. Depending on the exact species they can grow to sizes of up to (and sometimes over) 2 feet. The majority of species are brackish fish which will require some salt to be added to the water they are kept for their long term health. Like most catfish they are predatory and will eat any tankmates which are small enough to fit into their mouths.