LMAO!!!
Sorry...
What size tank is the Trimac pair in?
I had my pair (m-10~11"; f-6~7") in a 4x2x2 120 gal for about a year. In one back corner I buried several layers of rocks and slate in about 2.5 square feet and put an adult pair of Convicts (m-5";f-4") in with them.
The Male Trimac spent most of his day attacking the rocks until he finally killed them both.
I tried another smaller pair and amusingly he didn't bother them nearly as much. He eventually learned a little game of grabbing the male Convict in his mouth and then raming the glass. This happened about 7 times before it killed the Convict.
Once the female was by herself she decided she wanted to mate with the male Trimac. She was quickly eaten (eaten, not killed) by the female Trimac.
In my fairly limited experience with Trimacs, I don't see any fish working for the application you are looking for. I was hoping the Convicts would work and they had extensive caves to move around in where the Trimacs couldn't get to them. But Trimacs are smart and any fish will eventually come out to "stretch it's fins"...
I suspect something like an adult Red Tail Catfish would work well or som eother kind of very large catfish, but it's unlikely you have the space in the tank for something large enough to not be bothered by a breedin gpair of Trimacs...