# A story about fiddler crabs and how I (almost) succeeded in making docks



## organometallica (Oct 24, 2012)

So I wanted to post here to talk about a recent half-success I had with some fiddler crabs in my 20G salt tank. I recently took in six crabs from the local university, rescuing them from euthanasia following a teaching experiment in an A&P lab. Having just set up the salt tank, I figured I would add them in for some fun.

However, the salt tank was always meant for fish, and so I wanted to make sure there was plenty of space. I originally went to Petsmart looking for a turtle dock, thinking I could rig that up into something, but they didn't have any. Instead, I went across the street to Target, got some suction cup soap dishes, filled them with sand, and put these in the top. To make sure they could get up, I tied some shoelace and dangled them in like rope ladders.

Initially I was enthused with the results; three of the crabs immediately figured out how to climb up the rope, get in the dish, and jump back in. At first, they seemed to even play around, jumping off and climbing back up. Sure that the others would figure it out as well, I went to bed. The next day, I noticed that it seemed to only be the same three males that were succeeding in getting out; forty-eight hours later, the male that hadn't figured it out had died. Panicked, realizing I had inadvertently caused a natural selection situation, I went to the store and got some rocks & artificial driftwood and built a tower. Now the other two remaining crabs have figured it out, it seems, and now they appear to be swimming happily.

Long story short, much like humans IQ varies in a crab population. Some will climb to safety, others will just look to the sky and drown.


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