You don't say how long this has been, and that may be the issue. Fish do not like being moved to a different environment. This is a bit hard to explain, but moving most any other animal is usually problem-free. But fish are so tied to the water chemistry and environment that any change can be highly stressful.
It is actually better they not eat, as this will limit the waste entering the system and the water quality will be better. Not feeding them for a couple days wouldn't hurt either.
BTW, when they do spawn, the parents themselves will eat any eggs they find. Unless of course you remove the parents. Some eggs may survive, and then the fry if they can find sufficient microscopic food and have thick plants to hide in may survive. But don't expect large numbers.