We need a lot more information to be able to help you.
Tell us about your axolotls: How old? How big? What other symptoms, if any? Do you have some pictures?
Tell us about the tanks they are in: How big? What kind of filter? What decorations? What substrate (if any)? How long has it been set up? Pictures can help here too.
Most importantly, tell us about the water: What temperature? What pH? How much ammonia, nitrite, and nitrate? What dechlorinator (if any) do you use? How often do you change it? The reason this is usually the most important set of questions is that often, it is poor water conditions that directly or indirectly cause axolotl illnesses.