Sea Urchins

[ChilisREasy]

i was wondering if sea urchins would harm corals since everything they touch gets stabbed or stuck to them. & would he kill my hawk that likes to sit on nearly everything in the tank ?

[Geoff]

depends on the urchin. there are a few urchins out there that can kill critters that get stuck by them, including you. these are luckily not very common in the aquarium trade. the normal black urchins encountered in the trade are harmless. i have kept and still keep urchins in my tank. they are great at keeping the LR clean of all algae and biofilm. keeps the LR renewed.

G~

[texfromkansas]

I just bought my second pin cushion today and they are awesome. I have a flame hawkfish and multiple shrimp and they leave them alone. The urchins are great cleaners and don’t bother the corals at all.

[Geoff]

Welcome to TRT, texfromkansas!!!



G~

[ChilisREasy]

i was going to get pink, blue, or green ones. are they deadly to fish or corals ?

[Geoff]

the few that are deadly are deadly to anything. they tend to be extremely brightly coloured. mostly orange and red.

G~

[VWD]

Welcome Texfromkansas!!!

[KitKestrel]

Hi,

I have done freshwater for several years, and just recently set up a saltwater reef tank for the first time. It's a blast A couple of weeks ago I got a purple pincushion urchin who has done a great job cleaning up the hairy algae and has decorated himself with various bits of debris. Today I saw him clinging to the edge of the live rock and small round tan blobs were periodically coming out of an opening at the top center of his body. It went on for a good 7 or 8 minutes, and resulted in a cascade of blobs on the rock and the sand below him. I am most puzzled - firstly I thought echinoderms had only one body opening, and secondly what on earth is he doing?! Is he pooping? Or is this a spawning behaviour? If the latter he's (she's?) out of luck, as there's only one of him in the tank!

I've uploaded a video of it to YouTube. Any opinions and/or info would be greatly appreciated. http://www.youtube.com/watch?v=zgo3DnwdoCc

Thanks!

Kit.

[Geoff]

Welcome to TRT, KitKestrel!!

:welcome:

the urchin is just taking a dump. it is usually the colour of the LR. when urchins eat they scrape a way a layer of LR along with the algae. this is how they excrete the bits of LR.

G~

[KitKestrel]

I thought that might be it! Thanks for the info, and for the welcome!

Kit.