I don't know what other ingredients are in the human capsules, but I would try to stick with something that is just fish oil. I'd also make sure the ingredient list identifies the type of fish oil, if it just says generic "fish oil," I'd steer clear. I use Grizzly Salmon Oil for my dogs, but I have used a combo Omega 3-6-9 capsule in the past that had, if I remember correctly, oil from sardines in it. It may have had other fish oils too, but I do know that it listed them all specifically.
Regarding the Vitamin E, check to make sure you're using natural Vitamin E and not synthetic. It should say "d-alpha-tocopherol" and not "dl-alpha-tocopherol." L is for loser, good way to remember it.