If you know much about fish, my Dr told me, if I am ever wondering, to stay away from fish that eat other fish. But, he even said a can of tuna per week would be alright, but no more. So, fish sticks, even if they have a bit of mercury, I am sure would be alright. Honestly, though, fish sticks are often so processed, there may not be much actual fish in them anyhow! Enjoy, and just like Heaven said, everything in moderation is just fine. My Dr tells me that all the time.
I have learned that I can keep going long after I can't.