getting an axolotl soon, tips appreciated!

I've been incredibly fond of axolotls for years now, and I've decided getting one is the way to go. Before I order one and start buying supplies (I can't find any breeders or petstores selling them in Arizona) I just want to try and get some advice of a few things first.

I've decided on going for a 20 gallon tank to house one axolotl, although for the first few months I'm going to have to buy a tank separator to house my friend's as well until his tank will finish cycling (he's going to buy his after mine, and wants to keep it in a tank where the bacteria is already colonized and stuff). But I was thinking, even with housing a second for a while, would a 15 gallon be a wiser choice?

Also, from anyone's personal experience, what's the best type of food/most nutritious for an axie? I've heard bloodworms are okay, but I've also heard they can carry parasites and can throw off the ammonia levels in a tank pretty bad. And does anyone have a preferred filter? Or even water cooler brand? Being in AZ, the water will be too hot to keep an axolotl in, so I'll have no choice but to buy one.
I've been to axolotl.org and read a majority of the faqs on axolotl husbandry here as well, and I think at this point I'm just down to fine tuning the details before I get everything set up. Any tips are greatly appreciated!

(eep, and does anyone know how axolotls are shipped? I found a place out of state that sends them, but I'm a bit worried about buying one from them since it's probably incredibly stressful on an axie D: )

As far as tanks, bigger is always better. Go for the 20 (long).

Earthworms are your best bet as far as staple foods. Good choices also include frozen bloodworms, crickets, waxworms, decapitated/freshly molted mealworms, and any other 'bug' type thing. The best is a good mix of things.

As far as filters, a small canister filter will be good in a tank of that size. You can also use a waterfall type filter, although these usually need to be baffled somehow.

ahh, thank you for the input! I didn't know about some of those bugs being good for them. And I think I will go with the 20 gallon after all

I'm not sure how I'd keep the waterfall filter from being too violent, so my best bet will probably be with a canister filter.

thank you again!