Kate, I am sorry for your loss, and I feel your anger. There is actually a lot you can do. Very simply... COMPLAIN! Make some noise, get someone's attention, and let them know that you are angry. Mind if I ask the name of the pet store and what state you are located in? You can PM me this info if you don't wish to post it.
Unfortunately, many people don't go so far as to actually complain, which means the store either never knows they did something wrong or they figure it doesn't matter to the customer, so why change what they're doing?
Something else I would do is to visit the following links, print the pictures of a real fire eel, and present this to the manager and ask him/her to please explain? Do your homework about both eel species before going in there, know what you're talking about and then let them know, too. http://www.aquascapeonline.com/store...ire_eel_lg.jpg http://images.google.com/imgres?imgu...3D10%26hl%3Den
It's hard to tell from your picture, but your eel appears to be a snowflake eel. http://www.richard-seaman.com/Wallpa...flakeMoray.jpg
This is a wonderful species, and the last one I cared for was over 3 ft long, and quite the character. It's still thriving, in full saltwater. The misconception of how to properly keep a snowflake eel is incredible, and partly due to their natural habitats and where they are wild caught. They do spend part of their time swimming through brackish and even freshwater areas, and they do best when their natural habitat is mimic'd as much as possible, with gradual changes from one to the other, but full saltwater should be the majority of their environment. They will do much better in brackish than in freshwater for short times, but still will need full saltwater, eventually. They also require a large tank, they get huge and are very messy eaters. They also don't see well, so some people can find them tricky to feed. These eels also stress easily, which will cause color changes, shedding of the slime coating, various other illnesses, and eventually death.
If you wish to try again to keep one, I would enjoy coaching you through the steps to doing it safely. Feel free to ask anytime.
Let us know what happens with the others at the store... and GOOD LUCK!!!