Do not put gravel in the tank. You can use sand if you want but a bare bottom tank is just fine. you can put plants in there, real or fake. If you go with real ones make sure they will survive in the environment suited for an axolotl tank (cold temps and low light). If you choose fake plants, silk ones are the best or anything that doesnt have a sharp edge or that can be eaten by the axolotl. Axolotls need a place to hide in so you should provide a few good hides for them. I would probably only put one adult axolotl in a 2 foot tank.
