Problem with urchin?

[antigonus]

Iv'e had a pink pincushion urchin for around three weeks, and a day or two ago I noticed a few spines laying on the sand bed, and it didn't seem to be moving much. I thought it might be a nutritional issue as the urchin has consumed all the GHA in the tank, so I spot fed it a couple of nori sheets, which it seemed to eat. 

 

It's still clearly alive, but for the past two days has only been moving around on the same cluster of rocks, while before it crawled all over the rock work, substrate and glass. I tested my water just to be safe, and everything seemed fine, ammonia and nitrites and 0, nitrates between 0-2, and Ph 8.3. 

Here are a few pictures of it

 

Does anyone know what might be going on? 

[BlennyBoi]

i have heard sick urchins drop spines. maybe a disease?

[uwharrie]

There is a lot of algae on that rock. Could be it is just hanging out at the buffet longer

 

[antigonus]

12 hours ago, BlennyBoi said:

i have heard sick urchins drop spines. maybe a disease?

That's why I was concerned.

[antigonus]

6 hours ago, uwharrie said:

There is a lot of algae on that rock. Could be it is just hanging out at the buffet longer

 

It's possible, but I am pretty concerned about the loss of spines.

[Rob22]

Urchins lose spines sometimes just like a dog sheds. A few spines isn’t really something to worry about. If it starts dropping a lot of spines you may have an issue with water quality. I know you said your nitrates are 1-2 but you have a lot of algae on the rocks and on the glass that are consuming them before they show up on a test. It’s likely just either full and not expelling energy to move around or it’s found something on the rock it likes and is eating. They will strip the coraline algae off of your rocks, perhaps it found a patch it likes. 

 

Its really tough to tell how they are doing, but yours have those sticky feelers out. Looks as healthy as my purple urchin. I periodically find spines from all three of my urchins and have had them for months to years depending on which one. 

[antigonus]

23 minutes ago, Rob22 said:

Urchins lose spines sometimes just like a dog sheds. A few spines isn’t really something to worry about. If it starts dropping a lot of spines you may have an issue with water quality. I know you said your nitrates are 1-2 but you have a lot of algae on the rocks and on the glass that are consuming them before they show up on a test. It’s likely just either full and not expelling energy to move around or it’s found something on the rock it likes and is eating. They will strip the coraline algae off of your rocks, perhaps it found a patch it likes. 

 

Its really tough to tell how they are doing, but yours have those sticky feelers out. Looks as healthy as my purple urchin. I periodically find spines from all three of my urchins and have had them for months to years depending on which one. 

Thanks for the advice, I'm probably going to do another water change out of my regular schedule just to be safe.