Urchins

[nobody]

i was looking at www.thatfishplace.com i normally go to the store and..........i read a thread before about urchins eating coraline alage..........i really like a few of the different kinds and from what i read they are very easy to keep......... but if they eat coraline why would you want to have them

[dobejazz]

By eating the coraline they help it spread by releasing spores

[seshapir]

Originally Posted by dobejazz

By eating the coraline they help it spread by releasing spores

That is so interesting! I never knew that.

[nobody]

so this is a good thing..........these are the two i like

Rock Urchin You Pay: $ 9.99 In Stock: Yes

Pin Cushion Urchin You Pay: $ 9.99 In Stock: Yes

[Geoff]

yep, urchins are a great way to spread corralie throughout the tank. since thier teeth are so hard they can scrape down to bare rock when eating algae (which can include corraline). bare rock is needed for corraline to grow. it can not take hold if there is already algae in that spot. they are also messy eaters. the broken pieces of corraline that they do not eat will be released into the water column. these spores could then land on these newly cleaned pieces of LR and take hold.

G~

[jenajet]

What are requirments for urchins? Low high light? Do they harm corals?

[Fly Guy]

Be warned though that if your tank is acrylic they also can "spread" the scratches around as well as the coralline.

[wharyat]

Originally Posted by Fly Guy

Be warned though that if your tank is acrylic they also can "spread" the scratches around as well as the coralline.

Yep, they leave nice little star shaped gouges in an acrylic tank.



Only requirements are; large tank (the test can reach up to 12" across in some of the common aquaria species), and perfectly stable pH and salinity. They should not be kept in a tank without an auto top-off, along with all other echinos.

[jenajet]

So they would not be good in my 24 gal? Why do they need auto top offs?

[wharyat]

Originally Posted by jenajet

Why do they need auto top offs?

An auto top-off will keep the salinity from fluctuating too much and too fast.

All echinos (starfish, cukes, urchins) use a water-vascular system; where the water is used to inflate and deflate tissue allowing thier mobility. So if the salinity or any other level fluctuates too rapidly they are forced to purge their system, to equalize with the surrounding water, which sometimes destroys tissue and they end up literally falling apart from the inside out.

[jenajet]

Thanks for input. I dont think urchin is for me then. Tank too small and not auto topoff. Good to know.