I think anything is worth a shot unless it's completely obvious it won't work.
For every thread on here where someone says a certain combination won't work there are 2 other people that state they have that combination and it's working well for them... then the flame wars begin
In all reality, as long as you have a separate tank available in case bad stuff happens and you keep a close eye on things and make sure they are both fed and have enough space to be comfortable in then give it a go.

Obviously they should be close to the the same size and you should have a respectable sized tank.
People don't learn until people try