Yes, they do. if they're in a tank put some shells in it for it to swap them over. Otherwise no they don't.
I have never kept them but at least a 30ltr tank is advised by experienced growers for one Axolotl and an extra 10 ltrs needs to be added for each extra Axolotl.an axolotl tank should be at least 10 gallons.
They like a bit of old pipe so you can make a little tunnel for them to hide in.
Yes you can. Go to a pet shop and buy a bag of shells for fishtanks. These are good because they won't introduce bacteria to the tank.
Yes.
If axolotls breathes oxygen, then yes.
No you shouldn't put egg shells in quantity in your septic tank. I work for a plumber and we pump 20 tanks a day and you can actually see the eggs shells in the tank. They tend to make everything really hard and alot hatder to pump the tank, that in turn makes the cost to pump the tank a little higher. Some think that egg shells sharpen the blades on the disposal.While a disposal and a septic tank don't do to good together because for some reason the ground food doesn't break down it just sits on top. Try ice instead of egg shells in youe disposal. That will sharpen your blades {ever so slightly}/
It is alright if your axolotl swims around at the top of their enclosure. This may however signify that they need more oxygen and that you should clean the tank more often.
No, this isn't a good idea. The betta might nibble the axolotl's delicate gills, and a big axolotl could swallow a betta, but the most obvious reason why the two are incompatible is that they prefer very different water temperatures. Bettas are tropical fish that require relatively high temperatures of 25-30 degrees Celsius, whereas axolotls prefer their water cooler, around 15 degrees.
Molch, small water bowl empty shells and logs and small caves. put them with 4-5 different crabs
There are a couple of reasons why your axolotl might not be eating like temperature of the tank water and if the water is being cycled, and if you are feeding your axolotl only one typeof food maybe try something different,
I would say that it would depend on the specie. You should spot clean feaces as soon as you see it so a full clean out could probably be done once a week maybe a bit longer