Sally lightfoot crab sick?

[rmorse]

Hey guys, I am BRAND new to this hobby. I have a 29 gallon biocube that has been up and running for about 3 months. It has a black molly and a six lined wrasse in it, as well as (I hope) 6 blue legged hermit crabs.

30 lbs live rock, 30 lbs live sand.


I just added a sally lightfoot crab to deal with the crud on the bottom, and it looks sick. It immediately started eating, but also scratching itself. Also, the little "hatch" on its belly keeps opening, exposing red (i think its his gills? )


Any advice? I hope this isn't a stupid question....


Bobby

 

[rmorse]

Ammonia: 0
Nitrite: 0
Nitrate: 20 ppm
PH: 8.2

Hydrometer: I need a new one. I think it is at 1.023, but I have a oceanic plastic one. Air bubbles throw it off....

 

[water_baby83]

Well, a nice clear picture would really help. Sounds like one of two things here.
First, your crab may be stressed. Your Nitrates are high, and need to be lowered immediately. And, like with any animal, acclimation into a new environment is essential. Did you acclimate this crab properly? On the whole, Sally Lightfoot Crabs are quite hardy and rather easy to care for. However, they cannot tolerate poor water quality. Nitrates are a toxin to fish and inverts and if not kept well within the safe ranges, it can lead to their death, and a definite reason for your crab to be in distress right now.

Aside from that, because obviously we are not their to witness it personally, and have no picture for reference, I will toss out another probable explanation - a less worrisome one (but regardless, your nitrates still need to come down.)
Your crab may be getting ready to molt, which is why you have witnessed a "scratching" behavior, and why you also may have seen a "thatch" as you say open on the underside of the carapace. Being that all crabs have exoskeletons, molting (the shedding of old shells - like a snake sheds their skin - to make room for a larger shell as their body grows), is a process that can happen rather frequently in younger crabs depending on their growth rate, which in turn is determined by environmental influences within their habitat.
If this is the case, make sure you are watching the levels of trace elements and minerals in your tank, and these are needed for the regeneration and hardening of newer shells. In addition - as with any crustacean, Iodine, Calcium and Strontium (usually combined with Molybdenum when sold) are vital to their health.


It's really hard to say since this is a new addition, and no pictures, however one of the two above situations is probably what you are experiencing with your new crab.

 

[rmorse]

Awesome, thanks water baby. I think it is a combination of both acclimation and possibly molting. Me, being the idiot I am, actually listened to the LFS owner when he told me to just float the bag then drop it in. After today, never again....I will drip acclimate EVERYTHING. This is my first time with a salt tank, so it is all new to me. He has calmed down a bit though.



Oh yea, I found out it is not actually a sally light foot. Instead, the crab I have is a flat rock crab, or "Percnon planissimum"

 

[water_baby83]

Awesome, thanks water baby. I think it is a combination of both acclimation and possibly molting. Me, being the idiot I am, actually listened to the LFS owner when he told me to just float the bag then drop it in. After today, never again....I will drip acclimate EVERYTHING. This is my first time with a salt tank, so it is all new to me. He has calmed down a bit though.

Oh yea, I found out it is not actually a sally light foot. Instead, the crab I have is a flat rock crab, or "Percnon planissimum"

Yes, everything needs to be acclimated.. Even snails should be. The majority of advice you will ever receive from LFS employees - unless they are the rare few who are actually educated, can be written off as crap. And sometimes, what you need to do, ends up being the exact opposite of what they suggested. LOL.

And when it comes to the species, there are two which are commonly referred to as Sally Lightfoot crabs. One, is the Percnon planissimum, as you listed, and the second is the Percnon gibbesi.
"Flat rock crab" is just another nickname given. It's still also called a Sally Lightfoot. Confused yet? LOL That's why its imperative to know the scientific names,

 

[rmorse]

Ok. Well, I did a partial, and the scratching increased TENFOLD. I really don't get it, and I am really worried about the little dude. Also, I tested my tank's salinity after the change, it is now 1.022. Should I be worried?

 

[water_baby83]

Ok. Well, I did a partial, and the scratching increased TENFOLD. I really don't get it, and I am really worried about the little dude. Also, I tested my tank's salinity after the change, it is now 1.022. Should I be worried?

OK well since we took it to PM's, I am going to post those here for others to benefit should they encounter a similar problem, if that is ok with you?

 

[rmorse]

Thats fine. Sorry, I went to bed, didn't see this before I went to sleep....

 

[water_baby83]

Hey water baby,

Sorry to bother you in a pm, but I am really really worried about this guy, and you seem to be the only one who knows what they are talking about. I did a partial, and he is itching REALLY bad now. I seriously think he is going to tear off his legs/rip his eyes off. I feel so bad, I can't stand to see an animal suffer. This whole salt thing is still new to me. Also, after doing the partial, the salinity level has dropped to 1.022.

Any suggestions?


Thank you sooo much for all the help you have given me already.

Bobby

Ready - and breathe.

try to tell me in detail what you are seeing when you said that he is "Itching" really bad. Describe his behavior as best as you can. Also, any way you can get me a clear and up close picture??

The salinity will always drop when you do a water change if you are not adding the proper amounts of salt back in. How many gallons in your tank? Have you done a full panel test of your parameters yet? If not - do so, if you have, what did they read. (Not the one from a few days ago, do one right now.).

You are no bother, don't worry about that. Try to answer those questions so I can provide more info.



Em

Ok. *breathes* The crab is taking his back legs (the 4 long legs on either side) He is rubbing the legs together vigorously. He will also take his claws and actually pinch himself on his legs and rub his eyes with them. The best way I can describe it is he looks like he has a really bad itch. He is hiding right now, so I don't know if I can get a good picture, but I will try. I am also off to do my tests. Thanks again!

Bobby

Ok, I don't think I can get your picture tonight...I can't find the little guy anywhere. The tank is a biocube 29 gallon, so probably abour 18-20 gallons of water. Tests results are as follows:

Ammonia: 0
Nitrite: 0
Nitrate: 20 ppm
Salinity: 1.022
PH: 8.2

While testing it, I thought the water felt really really warm. So, I ran, got a digital thermometer from one of my other tanks, and stuck it in. The temp came out to be 83.4, so I turned the heater down.

Bobby

Ok first, here is what you need to be shooting for;
72-78° F
sg 1.023-1.025
pH 8.1-8.4

Mix some salt in some warm water with the salinity reading 1.028+, make about a gallon. Then pour it slowly into the tank under an area of high current. When mixed, test the overall salinity again, it should raise it to at least 1.024. Turn the heater waaayyy down, right now you are cookin your tank, lol. It needs to stay at about 75 degrees F.
And im wondering why even after a water change your nitrate is not going down. Ima think about that for a min. That could be a big cause for the added discomfort. Also, are you adding Calcium, Strontium, Iodine and Trace Elements into your aquarium? They need these to support their exoskeletons or they can develop a condition known as soft-shell/shell-rot.
Don't freak out if he loses a leg or two, they are jointed accordingly (as this is a common escape route for them in the wild when preyed upon). They can reginerate them rather quickly (another reason you should keep the supplements in the water at optimal levels).

No, I am not adding anything. I work at a Petco, so I can pick up the Calcium, Strontium, and Iodine there. What are trace elements? And I will do the other things you suggested as well.

Thanks,

Bobby

Kent Marine is the best - and the only brand I use and trust for everything.

Petco should carry them. The trace elements will be by Kent Marine and have a purple label (usually in a clear bottle, and the formula its self is a deep purple/blue). It's called "Essential Elements".
Kent Marine also provides the Calcium (yellow label), and the Strontium (as a double compound with Molybdenum) - Green Label.
Dosing instructions are on all the bottles.
Keep me informed.

-Emi

Let me know when you have an update for me.

 

[water_baby83]

Hey Emi,

Well, I woke up this morning, and went to check on the crabby. I saw it upside down, dead. I was extremely upset, but I then noticed it eating on one of the live rocks. It molted its entire shell!


However, it is still itching a bit. I am hoping that this crab just went through a painful molt, and that this is not the norm. Hopefully all is good with it.



Thanks again for all your help!

Bobby

LOL ya had me upset there in the first sentence I litterally had a 2.5 second brain crash thinkin "ok, what did I miss, how did this happen", then I read on and was like oh ok, I was right, *whew* LOL.

Itching is normal for all stages of molting - think about when you get a little sunburnt and once the pain goes away the itching starts because your burnt skin tightens and then starts peeling (same idea). His shell will be soft for a few days so he will be vulnerable to abuse from other tankmates so keep an eye out, and make sure you are adding those supplements (I hope you purchased them), because its those that provide the necessary elements for exoskeletal regeneration.

And no problem at all, you are welcome. Glad he's good to go and gettin bigger. Well done papa. lol.

-Em

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