An old friend of mine, one of the old-school naturalists, successfully kept muds for years...as I recall he used a 30 breeder-style tank with a mulch substrate and a large water receptacle and a hidebox, nothing too fancy. The snakes were gentle and easygoing thanks to constant use as educational animals. If memory serves, he housed them alone to prevent riots at feeding time. When possible he tried to get them switched to frogs (a little cheaper) whole fish (other than goldfish) or still-naked rat pups. He advised that this can take 6 months and still some won't make the switch, period.

You can find sirens and amphiuma for sale at a variety of sites on kingsnake, some through the feeder section, others in the pet classifieds. Exotic Pets Las Vegas has carried them; so has a feeder-oriented site called Swamp Monsters of Florida. No doubt there are others. It might be worth offering to buy dead or damaged specimens (for scenting, not feeding outright, as you don't know what killed them) from a dealer at a reduced cost.

Mud snakes themselves are generally not commonly offered for sale, precisely because of the issue of insurmountable prey difficulties unless you live in the South. I do know that when I've seen them, they've typically been under $100, and sometimes the dealer will kick in a frozen siren or amphiuma for scenting purposes. Because of their diet, GET IT UP FRONT as to how recently they've been wormed, if at all. If not, get the snake and a fecal sample straight to a qualified herp vet.

If you can, get it straight from the dealer on what the snake is eating and how often (remember that rodent-eaters and amphibian-eaters sometimes don't do well on each others' regimens.) Sometimes you get a break and the snake will be fully or partly switched.

I personally believe mud snakes are one of those snakes best left alone in the wild--to my mind, putting the snake through the stress of changing its diet, the headache of obtaining the main diet even for scenting, and the inroads on my sanity wouldn't be worth it. However, I would love one day to wake up in a world where these beauties are easily kept thanks to some secret unlocked by a diligent hobbyist--and who knows, you may be that hobbyist. So good luck on your endeavor and I hope at least some of this was helpful!

No problem--glad to be of any assistance, as the oddballs have always been my favorites.