Thanks for the quick reply Phishie ^^

It has, however, confused me a little. I don't know how truely reputable it is (though it does seem like an excellent site)but before posting here I had done some "research" on http://www.aquariumfish.net, and I made this list after sifting through the information there. I knew about the Fiddler crabs, they will have out-of-water access. You say that both Opaline/Gold Gouramis and Bala Sharks are not really suitable, but we've previously kept a Bala Shark with a group of platies and guppies, and until it died of Ick (new guppy brought it in) it was very peaceful around the other fish. Likewise, we recently added a group of Gouramis (2 Opaline, 2 Blue) and besides some mild chasing here and there amongst themselves they seem pretty passive towards the other fish.