Another idea inspired by a walk on the beach...
I have maintained a few freshwater aquariums in my time. I am also always fascinated by the use of aquariums in fish markets (as I've seen in my visits to Taiwan) which are also used by restaurants to hold live lobsters or similar facsimiles until someone buys one. Then they cook him up and someone eats him. Why not have that great experience at home?
Actually, I'd never heard of anyone using an aquarium at home as a seafood holding tank. What's really the difference between the two? I have a 30 gallon aquarium that's been sitting around without a real use since Katrina (the pump, filters, and other mechanics were destroyed, but the glass aquarium needed only a good washing). Why not use it to hold live animals until I wanted to eat them. After consulting a guy in an aquarium store (who was cooperative but seemingly appalled that I wanted to maintain fish to eat, and not as pets), I was assured that all I really needed was a decent filter, dechlorinator, and some aquarium salt. Balancing the salinity to hold fish that range anywhere from salty to brackish to fresh would be the real challenge. I have added salt to about 1.75% the suggested amount on the label. Not sure what the required % of salt is for a saltwater tank, but I'm guess-timating for brackish.
So, I bought a filter and that was that. I picked up a few blue crabs from a Chinese market to begin the trials. In the past, we would buy crabs only when we wanted to deal with them, and if you were preparing them for later they would have to be blanched, cleaned, portioned, and frozen. Most markets that sell live seafood are a distance away. Now, I can just pull out one or two of them suckers whenever I felt like eating fresh crabs. I'm only wondering how long I can hold them before they die. I'm also thinking about what and if I should feed them. Sure, if I'm going to eat them within a week, it's probably not necessary... but what if I use control of their food to add flavor to them? What animal proteins would they eat that may also increase their taste value? Would they eat fresh herbs? Cheese?
Now to find sources for live shrimp and compatible fish to try after the crab trials. It'll also be fun to catch them from the water before I eat them. I hope this doesn't turn out like the Simpsons episode where Homer keeps tries to grow a lobster at home and gets attached to it then accidentally boils it while giving it a hot bath and has to eat it... poor Pinchy!
Just to note... we do keep live crabs in South Louisiana as well, but that's in a wire cage enclosure that can be lowered or raised from the bayou, and not in someone's living room. The down side of that is sometimes snakes get in the holes, eat a crab or fish, then can't escape from the hole they entered due to their increased size. Then you got a pissed off water mocassin on your hands. We call this 'box' a vivier (pronounced vee-vyay).