I believe it was on subject. You don't listen to the information given. My advice, don't get the dovii, and get your other fish situated first.
You know the answer to your question before you posted, you were just looking for one person to say that you can do it, and in most cases no one will even do that, in which case you will carry out your desire anyway.
So please, go buy the dovii, and proceed to post about how you can make him color up more and get bigger faster.
Edit: The main reason it won't work is because a male dovii can easily grow larger than 20 inches, which means he won't have enough room. When you include a female, the poor thing will be relentlessly harassed.
And if you were to add hiding places for her, you reduce the amount of total area in the tank, considering a hiding spot for a 10+ inch fish, has to be quite large.
Is this what you were looking for?