Seems like what I went through, I had one around 6" that would eat and eat when I first got home, consumed barracudas, jaguar cichlids, prawns, krill, market shrimp, etc.. After a few weeks he just stopped eating, I threw a pike cichlid in there he mouthed it and thats it, he would hold shrimp in his mouth and then just spit it out. He passed away after about 2 months of this. Good luck just be very careful, I couldn't get mine off his hunger strike.