Advertisement Sorry for your loss! You did the best you could for him! I had not said anything previously as I hadn’t any idea what could be wrong if not pesticide exposure. Do you know how old he was? Some older T’s I’ve had exhibited a decrease in coordination, but nothing like a seizure, and roaches I’ve lost to old age (no hissers yet) have just slowed down until they passed. Were there too their symptoms or signs that make you suspect a parasite? I am not familiar with those that may affect roaches, although I would think a specific parasite unlikely as any that prey on hissers would not be found in the U.S. and hissers have been in captivity for a while now... Perhaps it was a genetic condition that revealed itself with age? There are certainly plenty such maladies that effect other animals and I would be surprised if insects did not have similar.