algae covered urchin

[MarkD40]

I have had sea urchin in my refugium for about a year who does a pretty good job keeping things tidy. Unfortunately he can't clean his own spines and has developed a rather thick growth of algae on them. I try to remove it manually but it is stuck pretty tight and I don't want to pull too hard. Any ideas on how this could be removed?

I was thinking about removing as much as I could manually and then dipping him upside down into RO/DI water for a few minutes to kill the algae. Perhaps even adding a little vinegar to the solution to rupture the cell membranes of the algae. I'm not sure if this algae coating bothers the urchin but it bugs me. Any suggestions on a safe way to do this? Thanks

 

[greenbean36191]

Echinoderms are very sensitive animals. Any chemical treatment, including RO or vinegar dips that is strong enough to kill the algae will also be strong enough to kill the urchin.

Is this a pencil urchin? If so, a gentle scrubbing with a soft toothbrush is your best bet.

If it's not a pencil urchin, are you sure it's not just picking up bits of algae to camouflage itself? If that's the case, as soon as you remove it it's just going to pick up more.

If it's not a pencil urchin and the algae really is growing on the spines then you have a sick animal, and getting it back to good health should be a higher priority than getting rid of the algae. Normal urchins have tissue that covers their spines and keeps algae from growing on them. If there's algae growing then the tissue obviously isn't healthy. If that's the case we're going to need to know more about the parameters and history of your system and the animal.

 

[skeeter-doc]

I say, put the urchin in a small shallow bowl of your tanks water, and then clean the spines by running a toothpick through them and pulling the algae off that way.

 

[MarkD40]

It is a pencil urchin. My tank is well established with solid paramers. Zero visible algae in my display. My idea was to dip him upside down avoiding the mouth. We fresh water dip fish so I thought that just dipping the spines would be OK.

Greenbean, do you still think that would harm the spines?

 

[rustybucket145]

Got any hermit crabs down there?

 

[MarkD40]

No hermits. Not sure they would help because the urchin stays on the glass most of the time. Was thinking about putting some mollies in the refugium to eat the algae but afraid that their fry would eat all my pods.

 

[greenbean36191]

Regardless of how you plan to do it, I wouldn't do a FW dip of any kind. Unless you lyse the cells first, most algae aren't that sensitive to short term FW exposure. Since the spines are just a big porous calcium crystal any longer term dips will likely end up wicking the water up towards the body, possibly causing harm. Basically, IMO it seems like drastic measures for an insignificant problem.

 

[MarkD40]

Took the pencil urchin out and put him in a deep bowl and removed the algae. Greenbean is correct. The algae was not sticking to the spines. The spines were entwined with chaeto and the algae was growing attached to it. Once the chaeto was removed the spines were completely clear of algae. Will need to be more diligent about keeping his spines clean.