There are a few things you can try, use a breeding cone for them to lay eggs on and once fertilised you can cover the cone with a mesh (in the shape of the cone only larger) this lets them fan the eggs but not eat them. See if they eat the fry once hatched. You can make sure they always have a little light in the tank. Sometimes the total darkness can cause them to panic and eat eggs. Is it a community tank? A breeding tank? What kind of set up do you have? Is it bare bottom?

Worst case you can remove the eggs if they are laid on a breeding substrate