I googled the same thing and came up with the same image after reading your post. I read the thread and it's actually a target mandarin being eaten. I did some more research and found that there are a few other cases of maxi's eating fish, but the fish are usually sick or dieing when they are eaten. I think it's probably a lot like other "reef safe" anemones in that they will eat fish if they get the opportunity because the fish is either slow, sick, or small. I know that I have a lot of maxi's in both of my tanks, and both tanks have tiny gobies and clowns. I haven't had any fish go missing, but I might just be lucky.
In my opinion it's a risk worth taking. And the odds that a maxi-mini is going to eat a healthy fish are pretty slim IMO.