Just an FYI re fish: I feed two of my dogs the Fromm Whitefish and Potato recipe because they need a lower fat content. I emailed the folks at Fromm to ask about the origin of their whitefish. I've always found them to be very responsive and thorough in answering questions and this time was no different. Here's the information they gave me about their whitefish:
"In the Whitefish and Potato recipe we use Atlantic Whitefish. Our fish products do not contain harmful levels of mercury, toxins, or radiation. Our fish comes from sources caught specifically for human food production. There are many federal, state and regulatory groups such as the FDA that are constantly monitoring the safety of all waters from which food producing species are harvested. The fish we use is clean, safe, and supplies nutrients of excellent quality."