I have a small crab that I collected at Laguna de Arnaud (outside of Treint y Tres, Uruguay)...
Using my Dollar Store plastic bin as a floatation aid, I became the first ever American to swim (the 400 yards or so) across Laguna de Arnaud to get to the far side...dragging along my dip net even!
The water was awesome temperature although not really clear enough to take good underwater photos. I found two crabs (attached to each other) under a rock in shallow water and caught a bunch of baby Gymnogeos, tetras, Cory cats and Jenysia livebearers (a few that I still have) in the plants.
Since my plastic catch container was full of fish and water and the liter of beer that I drank prior to my journey had begun to kick in, I opted to walk around the lagoon to get back to the van (vs. swimming). I startled someone's horse (that was grazing) in the area to the right of the trees in the second picture.
I had a fleeting thought of some kind of biotype tank, so I documented the substrate for posterity.
When I returned to the van, Felipe was having an animated conversation with the Mayor of Treinta y Tres (congratulating Felipe for bringing tourists to his town?...or more likely everyone in Uruguay knows each other). Either way a great time was had by all...we harvested the Crenicichla (pikes) that swam into the minnow traps that I set before my swim... and off we went to dinner....
So what happened to the other crab (I collected two)?
He/she had a friend until the friend crawled out of their bin and into the 150g full of fish below...
The little crab molted for like the 3rd or 4th time last weekend but is still only ~2"...
Matt
these are the only FW inverts i keep.. 
