sick sea urchin


My rock boring sea urchin came on my rock well over a year ago dime size. Now, it's full grown and usually active. This week it has stayed on the sand next to the rock like it's trying to climb it, but can't. A few of it's spines on top are laying sideways. I tested my tank and everything is as it should be. I only use ro water. I've been dealing with red slime. I'm doing weekly and bi-weekly water changes to siphon the slime from the rock. Could the frequent water changes or the red slime be the problem? I also wasn't running my lights only to feed the fish. How can I help it to the top of the rocks? Tongs? Any help would be appreciated. I've grown fond of the spiny guy.


i believe you mean a Pencil Urchin aka rock boaring urchin. Mine would sometimes sit for days in the same spot when he found something to eat and occasionaly his spines would lay sideways. I wouldn't worry until he starts to lose spines, Pencil's are quite hardy and if you've had him this long i don';t think he's in any trouble.
keep an eye on him to see if anything changes.


Active Member
A pencil uchin (Eucidaris) is not the same as a rock boring uchin (an Echinometra). You can search on google for these terms but nearly all hitch hiker urchins I am aware of are Echinometra. I am concerned by its behavior which is quite possibly tied to the cause of (or treatments for) the slime. What are your nitrates like? How old are your bulbs? Any ideas why you have this slime issue? I would do some research on why it is there. Uchins, like other echinoderms can be quite sensitive to pH and salinity fluctuations. However, the common rock boring uchin is a tough one, as you know, since it came in on your LR. They are commonly exposed at low tide.