Update: Lost my armatus. He tried several times take down one of my datnoids and took a real deep dorsal spine injury to the eye. The datnoid eventually died from the stress of repeated stalking by the armatus.
My armatus lost vision in the eye (fixed pupil) and had difficulty competing for food, growing weaker over a period of 1 month. Eventually developing exothalmus (popeye) and subsequent septicemia (blood streaked fins and labored breathing). Was unable to get successfully get antibiotics moving him was not a option. Did try a last ditch futile effort to force feed antibiotics when it was apparent he was going to die without intervention but he was to far gone.