Can a Red Oranda eat a Neon Tetra

Question
I am a bit confused becasue I gave my sister a Red Oranda Fish which is very beautiful. However later on she decided that the fish was lonely and bought six neon tetras. In the last week only three are left. She also bought a vaccum fish I am not sure what its called. but it sticks to the glas and is spotted.
The water in the tank is changed every week; because Cleo is very dirty. It is a new tank. But is she eating the neons?

Answer
All fish will eat a fish that fits in its mouth. If the neons are smaller than the fish's mouth, they may be eaten.

However it is more likely the fish just died, and the pleco ("vacuum fish") ate its remains.

Tetras are tropical, goldfish are coldwater, they should never be mixed or one or the other will die.

-Nick