Fiddler Crab Losing Limbs and Dying

The friendliest place on the web for anyone with an interest in aquariums or fish keeping!
If you have answers, please help by responding to the unanswered posts.

SebastianS

Aquarium Advice Newbie
Joined
Sep 27, 2016
Messages
3
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?
 
Thank you for the response.

I am pretty certain that one of the females is dead. The other spent some time last night moving in and out of her burrow. She came out entirely this morning and has been lying in a strange position ever since. I have not noticed any movement and am afraid she may not pull through either.
 
If it was fish I'd suggest a water test as first check. Is that so important with crabs? Also wondering if anything else changed in the last 24 hours. Sorry! Just seeing if any ideas of use until someone more knowing comes along.
 
Again, thank you for your response.

As an update, the last one died yesterday as well. I would assume that it's something to do with a change in their living conditions because all went from seemingly healthy to dead within very little time. I did do a 50% water change two days before the male died but made sure to keep the same specifications as I had been. That was also the day that I first tried adding the freeze dried blood worms to their diet. I'd just picked up the Tetra brand worms. Up until then, they'd been eating namely commercial crab food, dried shrimp, algae discs, fish flakes (with the occasional small bit of blanched zucchini). For the most part, I just put a bit of each here and there so they could scavenge but they all had their favorites. I don't think they really bothered touching the blood worms, in all honesty. I cleaned out old food from their tank daily (more often with the algae discs because those tended to smell pretty bad and they were living in my bedroom).

I'd also recently put a new water bowl into the tank hoping to get them acclimated to it for when we would have had to travel. I'm a college student so, if they had survived, they would have spent winter break in another tank back home (I have an extra 10 gallon at home because my goldfish outgrew it several years ago and has since been living in a 20 gallon). I was hoping to create a mini habitat for them for the eventual ride home. The bowl itself was the medium-sized Fulker's corner bowl. I'd assumed it wouldn't be harmful to fiddlers as it's marketed toward hermit crabs. I made certain to give it a thorough cleaning before placing it inside. I'd be pretty upset if this is what killed them seeing as I bought it with the thought that my crabs would be with me for a good enough chunk of time to warrant a travel habitat.
 
Back
Top Bottom