My Snoopy (beagle) has IBS and with several medications we were able to control any further IBS attacks. The food I put him on is Lamb and Rice formula. I used Taste Of Wild for a long time until it got to expensive and I changed to Diamond Natural Lamb and Rice. I swear by Lamb as the meat. It's been two years (knock on wood) since Snoopy's last IBS attack. If the fish and potato doesnt work I'd try the Lamb as a meat ingredient in the food. Good Luck