When kept in captivity, they can suck the substrate from the aquarium along with their food, which can cause severe problems with their digestive system. Therefore, it is valid not to fill the aquarium with gravel but with sand grains not exceeding 1 mm. It is also not recommended to place objects with a diameter of fewer than 3 centimeters, which axolotl can easily swallow. Ingested stones and gravel are prevalent causes of death.
