A good friend of mine purchased one after seeing my fahaka devour all sorts of things.. He got it for $25 at an overpriced fish store, and I have seen tfdfish.com sell them for as cheap as $6 + shipping. They should be fairly common, but like most puffers, they are likely seasonal.
The care for them is the same as most the other puffers, but they do get boring. They sit and do nothing, and unless you are in to bringing over friends to watch big fish eat little fish, that's about the extent of it. With a 45g tank you might have alot of other puffer options, such as a couple F8s, a GSP, South American Puffers, Bronze Puffers, Dwarf Puffers, etc, etc.. It would be kind of a waste of tankspace to have an arrowhead in a tank bigger than 20g, because they don't need the swimming space at all..
