I also have a breeding pair of Jack Dempseys. They are Blue Gene, so roughly 1/3rd come out electric blue. The most of the excess fry get fed off to my fish and adult axolotls, who relish the treat. My advice would be to try it but keep an eye on them. Most get gobbled right up, however those that don't could start picking at the axolotl's gills. Also since the temperature is usually a lot cooler for the Axolotls vs Dempsey's any that remain shouldn't go back into your general fry population; the temperature swings/stress can cause them to come down with Ich. If you are concerned with them surviving/hiding in the plants you can always humanely pre-kill the fry by placing them in a container of water and putting it in the freezer, then treat your axolotls to some bite size Jack Dempsicles.