Hi Waterpuppy,
You need to select a suitable type of cave to fufill its purpose. Axolotls want a cave to feel secure and protected and also shade from the light. You would have to choose something that provides a dark/dim shelter. There is no point putting a clear bottle for example. You would also have to take into consideration the opening of the cave, is it big enough for your axie to fit in and come out?
There are many other 'caves' that can suit your tank, have you considered ornamental jugs/urns/pots? Pipes are popular. You can also construct a cave out of huge rocks/slate cleverly put together. You can also find some nice decorative hideouts for pets in aquarium shops.
Earthworms, bloodworms, blackworms and pellets are essential staple food types. Shrimp, fish, beef heart strips etc. are all optional treats. You can try sourcing for these items from your local pet store. But just in case you can't find any, i have also private messaged you a list of places that can deliver livefoods or products to your doorstep.
Cheers