I am sitting here on campus now.
I have crabs. 5 of them to be exact. They are small fiddler crabs.
They are in a 10 gallon tank, 1/3 filled with:
-Large bonsai (plastic) they can climb it well)
-False log. (hollow)
-Red and black rocks
-Mini Filter
-Fake seaweed, electric green.
All but the rocks and filter are half submerged so they can come up to wave and posture and fight.
They are all males, as illustrated by the one large claw, and one tiny claw.
They are named:
La Bamba: Biggest. Right claw Dominant.
Admiral Whitey: White backed. 2nd biggest. Right claw dominant
Citizen Snips: Left claw dominant.
Senior Longclaw: Right claw dominant.
Sun Tzu: Right claw dominant. Smallest.
They are sweet to watch.