Well, I have an empty 75 gallon and I plan on moving 3 angels and some tetras into it. I also may end up adding 3 more angels to equal 6 in all. Would I be able to add a crenicichla belly crawler to that mix? If not, would an adult female dempsey work out? I am considering trial-and-error but I don't want to risk either the angels or the pike or the dempseys lives. What's everyones opinion on it?