Horseshoe Crab Disease

[fishguy123]

Hi everyone, I have been raising 2 Horseshoe crabs for the last 5 years (1 is 3 yrs. old, 1 is 5 yrs. old)
They eat well, have a big tank and are usually great but the 5 yr. old has developed Green Algal disease.
His shell is turning green and splotchy, he's not eating much and moving slow. Has anyone had any luck treating this?
I have searched every post online on this subject and it seems there are no definite answers to this problem.
I would hate losing him after all this time as he is part of the family and very friendly.
Any help would be appreciated. Thanks
J.

 

[Jay Hemdal Verified Community Expert]

Hi everyone, I have been raising 2 Horseshoe crabs for the last 5 years (1 is 3 yrs. old, 1 is 5 yrs. old)
They eat well, have a big tank and are usually great but the 5 yr. old has developed Green Algal disease.
His shell is turning green and splotchy, he's not eating much and moving slow. Has anyone had any luck treating this?
I have searched every post online on this subject and it seems there are no definite answers to this problem.
I would hate losing him after all this time as he is part of the family and very friendly.
Any help would be appreciated. Thanks
J.

Welcome to Reef2Reef!

Horseshoe crabs can develop shell erosion issues, then algae grows on the damaged areas. The issue is that the shell itself cannot heal, only a new molt can repair the damage. Older crabs, especial males and those in captivity, begin to have a longer inter-molt period. This in turn allows for shell erosion to get a stronger foothold.
Can you post a picture?

Jay

 

[ISpeakForTheSeas]

Welcome to Reef2Reef!

Just to add a little to Jay's comment, what have you been feeding your horseshoe crabs?

 

[Stomatopods17]

Post a photo, its possible it'll come off next molt if its just algae 'staining' it. Happens with inverts all the time as long as it isn't true shell rot. My box crab comes out of a molt pure white, fades just slightly, and rn is completely brown and hairy from algae growth, sand, and detritus staining it. Horseshoes don't dust themselves off as well as other inverts can.

I'm really impressed you had horseshoe crabs that long, there's a lack of info out there cause there isn't many success stories at all with these animals. What's your setup/routine with them like?

 

[fishguy123]

Welcome to Reef2Reef!

Horseshoe crabs can develop shell erosion issues, then algae grows on the damaged areas. The issue is that the shell itself cannot heal, only a new molt can repair the damage. Older crabs, especial males and those in captivity, begin to have a longer inter-molt period. This in turn allows for shell erosion to get a stronger foothold.
Can you post a picture?

Jay

Hi Jay, thanks for the info. Sadly he died yesterday but i was able to take a good look underneath at his gills. He had a large greenish lump on one of his gills and the rest of his underside had areas of green spots. I am thinking the algal matter might have come in with some of his food. Not sure but he was only 5 yrs old and quite healthy before this.
He molted apx. 7x over the yrs.
I have made a hospital tank for my other one and will begin to empty the big tank and sterilize before putting her back in. Will keep you updated on her progress.
Again, thanks everyone.