Fiddler Crab Losing Limbs and Dying
Two weeks ago, I bought a few fiddler crabs (from Walmart, admittedly). Although this was my first time keeping crabs of any sort, I did my best to do my research to set up a decent environment for them. I made certain to give them both land and water – the substrate I used was a mixture of play sand and coconut fiber. I made certain provide dechlorinated water with a specific gravity of 1.010 (for this, I used the Instant Ocean brand). I bought several different kinds of food for them – dried shrimp, bloodworms, algae disks, and fish flakes. I’ve been maintaining a temperature just a bit above 75F.
I had three crabs in the tank (10 gallons) – two females, one male. They all seemed active at the time I purchased them and, until today, all appeared healthy. They were active and the male very regularly spent his time doing his “dance” for the females. They all seemed to get along very well.
I should mention that I’ve had the male for a week longer than the females. I made certain to monitor them during their first “introduction” to ensure there were no signs of aggression.
But, back on topic, eighteen hours ago, the crabs all appeared active and healthy. I did note that the male hadn’t done his dance in some time (he did it almost constantly for a week up until then) but he was still walking around and alive. That was all before I went to bed.
At night, I typically turn the light off but kept the heating pad on (the heating pad is attached to a thermostat to regulate the temperature). Upon waking, I noted that the crabs seemed generally inactive and that the temperature in the tank had dropped just below 75 (roughly 73 when I checked ). But, at this time, they were all alive, just sluggish. So, I put a bit of food in for them before going to class. I did not return for another 8 or so hours.
When I returned, I noticed that the large claw of the male crab had detached. It was a beautiful claw – nearly as big as him (he was roughly 2 inches from leg to leg – the females are half his size). It’d still been gripping a fake plant that he enjoyed climbing. I found the rest of him upside down in the water without his eye stalks.
Worried, I decided to check on the two females. Neither of them had lost any limbs (I should mention that the male only lost his large claw and eye stalks). Both were still sluggish (at this point, the tank temperature had reached 77F – this is, again, eight hours later, so I imagine it wasn’t a rapid change). One of the females is presently comparatively okay. She still moves, to say the least. The other, I’m afraid, may be dead as well.
I apologize if this is all a bit disjointed. I’m pretty upset. But I don’t understand where I went wrong. Why did my fiddler’s claw fall off? Why did he die? What am I doing wrong? Most importantly, what do I need to do or change to save the females?