The only suggestion I have for you (other than seeing a Vet if it persists) is keeping a daily log of the time you feed him anything, when he drinks H2O, and what is being fed to hopefully narrow down the culprit.
Who knows, he might have eaten something you don’t know about that has made its way out of his body and he’ll be back to normal in no time. 🙂
My mom has health issues and after pestering her for two years to keep a daily log of what she eats, drinks (including H2O) and the times consumed she has finally been able to eliminate foods that don’t agree with her and adjust when she eats her meals to improve her digestion.
