The most monster fish I keep and was keeping at the time I joined is/was an Asian Redtail Catfish. I didn't know a lot about fish when I joined and I had bought a book called The World of Catfishes, or something. They had the ARTC listed as Mystus Nemurus. I liked the mystus part and I went with the most striking feature, the red tail. So there you have it MYSTUS REDTAIL
I found out after joing that site that Mystus is no longer used, instead it is Hemibagrus. In fact the actual name for the Asian Redtail Catfish is Hemibagrus Wyckioides. But it is still arguably the most aggressive fish that can be kept in home FW aquaria. I still have that bad boy now more than 10" later.