I had to dump fish oil long ago. It just doesn't work with Vlad. He gets severe indigestion, and indigestion always makes me worry about his pancreas.
I'm now wondering about phytoplankton due to this article:
Fish Oil For Dogs: 5 Reasons You Should Dump It
In a nutshell, most dogs get too much omega-6 fats in their diet – and when that happens, it turns on inflammation in the body. If that inflammation is excessive, it puts your dog at risk for allergy symptoms, joint pain and many other chronic health issues.
The reason we want to add omega-3 fats to our dog’s diet is to balance out those omega-6 fats and reduce the inflammation that causes chronic disease.
So the whole point of feeding fish oil is to reduce your dog’s risk of disease or disease symptoms, right? You don’t give your dog fish oil to add omega-3 fatty acids or DHA or EPA to his diet … you do it because you love your dog and you want to make him healthier, free from diseases caused by chronic inflammation and, hopefully, make him live longer.
Edit: really might have helped if I'd put the link here: http://www.dogsnaturallymagazine.com/fish-oil-omega-3-dogs-safe/