Jackie every dog is individual and as such reacts differently but I can tell you that Thane does not do well on food that is primarily or completely fish protein based. Many dogs do though so don't base what works for Thane and worked for Met on whether its right for your particular dog. Thane does best on beef as the primary protein source (so did Met) When I tried to put Thane on a fish based food he got really sound reactive and his work was like really work for me. Thane's work has volleyed through this weird 2 year old phase but right now he is working awesome! He is eating a combination of solid gold mmillenia and a home made raw diet- working on weaning him completely to the latter. Karyn and Thane