I had my goldfish in with my O for a while. One huge fat goldfish, which I have posted on here somewhere always used to swim in Oscars path and just float ontop of his face???
My O hated this and pushed him out of the way and kept swimming. But as soon as he sat somewhere, the goldfish was right back on him....weird.
When I first got Oshie, I put him in with my goldfish, danios and other (what I now know as 'feeder fish')
Well, as you can see, they started to dissapear......yup, my O realised this was fun, and a good meal!!!