You are welcome!
On fish, I will need to think a little. You have a bit of variety on things...and lots of things which like to eat other things, if they are small enough or slow enough! So no small tetra snacks.
You would probably need something a bit larger which doesn't require perfect water, just due to the feeding habits of crabs and crays, they eat up lots of stuff but it can sit in the tank sometimes till they finish cleaning up the crumbs.
I think a German Ram might be a little too nice, so what about a Kribensis?Cichlid is smallish but tough...very attractively colored if you get a male, and wouldn't think pair as they spawn on the ground and may be a war with the bottom dwellers. I don't really know anything about the semi-aggressive behaved fish. So these are starter ideas, need someone experienced to comment on which might work better.
Someone recommended Congo Tetras! I saw some today at the lfs, very nice. VERY Big for a tetra, seemed to stay near the top 1/3 -1/4 of the tank.
How about Tiger Barbs? or Green Tiger Barbs...I haven't had them but they are attractive. Or if you'd rather go nicer fish, the Cherry Barb maybe.
Just make sure you get enough for their school or shoal.