99% of the time it would be death to the frontosa.
I knew a guy that had a couple 500 gallon aquariums, he stuffed everything in there, he would import quite rare fish.
ANyway, he had Moba in there with flowerhorn.
course remember this was a huge tank.
I also knew a guy who had a pair of red texas in with a frontosa colony in a 100 gallon tank. Some red's are mean, some are much less aggressive.
I had a female red texas in a 125 with frontosa colony, they ignored each other.
I should not say any of this, because now people will try it, and kill a frontosa.