Not true, alot of hybrids can breed. The reddevil is fertile, it has breed with another reddevil and produced a good 200 fry. and the female flowerhorn was bought as fertile.
Most hybrids can breed with anything thats willing to as they have no real genus origin. Thats the way I see it anyhoo.
When your FHxRD fry start to colour up, they may be like a red devil with a few flowerhorn markings or vice versa.
well, i put them in together, some lip locking at first than they seemed fine. came home from dinner to the flowerhorn beat the hell up. ( the rd is the same size as the flowerhorn! ). So i seperated them, will try again when the female flowerhorn is all healthy.
I had them divided for well over a week, they seemed to like eachother would swim side by side thru the divider. Guess they just wanted to kill eachother.