7-month springer not eating

Question
I am dog sitting my daughter's 7-month old English Springer, and he has not eaten all day today, and is eating a slight amount of green leaves, grass. He is on lamb and rice food twice a day, and ate last night fine. He did eat a pistachio nut (with 1/2 shell) yesterday. He has had a normal stool today, and is drinking only a slight amount of water. Should I be concerned? He is not crying or coughing. He did sneeze a few times last night. He went on a walk today and ran and sniffed as usual. Thanks for your help!!

Answer
Hello Susan it seems he has an upset tummy...dfogs rutinely eat grass or lettuce if ioffered when feeling under the weather, as long as he has his shots and is behaving almost noraml dispite not eatring he should be fine by tomarrow and eating if not I would have him checked at his vet.