The tank is a quite big 5ft 40 gallon one, but the lobsters only really use the bottom..they are extremlly easy to keep, and very rewarding. They eat almost everything that falls to the bottom, at the moment they are about 2-3inches long as they have just shed. As regards to where they can be kept, for one they are very, very hardy! And are really too slow to catch any fish..unless they are very sick or something - but they shouldnt be in the tank. So any good community tank.
Mine cost seven quid each, which is annnoying because I found them later that day somewhere else for three-fifty!
If you do get some, make sure you have some larger (calm) fish because this will stop the lobsters acting like they own the tank...because this will start to create agressive tendencies - unless thats what you want
Umm..they work well with tiger barbs, catfish, loaches, gouramis and the like. One last thing, they need somewhere suitable to hide, they enjoy to burrow a bit, so you need at least three-quarters of an inch of sand or gravel..also a pot or ship wreck for them to hide in at night.
The lobsters sould grow to 7 or 8 inches if you are lucky! (on their own in a massive tank, up to 14 or 16!!!!) Im gonner see if I can mix some hermit crabs in with them, but ill have to hunt around for some advice..
Anyway, hope that helps!
Jonny.