Fish ID please help

Hi guys , I rescued this catfish from an lfs near me. No one wanted to buy him as he has a broken fin. Front left fin was somehow damaged badly . It has healed now but is of no use. He is happy and settled in fine he has tripled in size over the last 3 months though. The guy at the shop said he is a synodontis altimera however his color and patter has changed almost completely since we have had him . So now I am not sure what he is. Please can someone assist me. This is the only pic I could get . He is to dam fast ! Even with a deformed fin.