Yes and no.... they will mix but both need different diets, frontosa are more carnivorous they need a higher protein content in their diet and will benefit from feedings of foods like prawn, mussle and earthworm whilst the torpheus need food higher in fibre such as spirulina and brineshrimp. Ive seen the mix on a few occasions and it does work but the tropheus can be a little too temperamental and acressive for the frontosa.