I have 12 chinese mantids that are about 6 months old. In the last week I have lost 3 and at least two others seem sick. Nothing in their life has changed as far as food, water, habitat, etc. They seem to go blind and stay on bottom of their homes clawing madly at the glass and air. Their eyes turned black and they quit eating. I have raised others with no problems. Crickets are their main food. I also feed them mealworms and dubias but they mostly only want the crickets. They don't go to bottom of house much to get non-climbing food. I've read that crickets aren't the best food choice but that's what they seem to like best. I buy crickets from major supplier (Bassets) and feed them lettuce, oranges, fish flakes and keep flukers quencher for them. Everything pretty much the same as done for previous batches of mantids that lived longer than a year. Any suggestions? Thanks.