Hitchhiker Urchin??

[ScruffyRubicon]

I see those on rocks at my LFS all the time. I've thought about buying a rock a few times just to get one as a hitchiker. They always seem to be deep in a hole.

[frankandmaura]

I got one too as a hitchhiker...mine doesn't move much, but I haven't looked at night to see if he is travelling. Congrats Kelli!

[tdwyatt]

hard to believe, but these types of urchins are most often found in tidal pools in the indopacific, where they may depend on the tide a good bit to bring them food items. They catch bits of algae and organic materials on the spines and use their long extended tube feet to retrieve these food items from the spimes to the oral opening. I do not know what percentage of their diet is based on grazing though.

[dobejazz]

I caught this guy on the move ! hiding out in my Blennies shell

[dobejazz]

[Wiskey]

Great pics Kelli! Neat urchen

Whiskey

[dobejazz]

Originally Posted by tdwyatt

Probably Echinometra mathaei or Echinometra oblonga, most likely E. mathaei, rock boring urchins/ They are totally reef safe, and will help control hair algae in the tank and improve coralline coverage with time. Google the above individuals for some pix.

HTH

Here is some info off Google
E. mathaei looks spot on

Echinometra mathaei - rock boring urchin
Description: small, light-colored urchin with short spines, thick at the base and tapering to a sharp point; typically greenish-gray or reddish-brown.
Size: usually 4-6 cm but up to 15 cm diameter.
Habitat: in holes and depressions on rock in shallow areas.

[tdwyatt]

Originally Posted by dobejazz

Echinometra mathaei - rock boring urchin
Description: small, light-colored urchin with short spines, thick at the base and tapering to a sharp point; typically greenish-gray or reddish-brown.
Size: usually 4-6 cm but up to 15 cm diameter.
Habitat: in holes and depressions on rock in shallow areas.

I have a red specimen that has been with me from the 1999 MACNA in Louisville, bought a ton of rock from Joy at that meeting and it was hidden in one of the neat rocks I got from her. I should take a picture of this bad boy...

[tellycoleman]

MY LFS today had a silver dollar size all black urchin. I thought about asking 4 it but didnt know what it would do to my tank.
Wonder would this variety be safe?

[steamboatwv]

He is gorgeous, of all the things i have tried, urchins do not take to my tank wish i could keep one but havent figured out what is up with that yet, congrats on yours

[tdwyatt]

Originally Posted by steamboatwv

He is gorgeous, of all the things i have tried, urchins do not take to my tank wish i could keep one but havent figured out what is up with that yet, congrats on yours

Urchins are echinoderms, and as such are very susceptible to swings in salinity. They usually require very slow acclimatization to the salinity of your system, especially if the conditions they have been kept in during shipping and at the lfs vary widely from your home system. With the exception of a few intertidal spp., you will need to be very careful introducing your new urchin to the tank, and maintain system with few if any swings in salinity. This means that you will need to employ an automatic top-off system for maintaining your evaporative water loss replacements to keep the swing in salinity associated with once-a-day top-offs to a minimum. Most fishes and corals can endure these swings, however, many echinoderms have a locomotion system that uses hydrostatic pressure to manipulate their tube feet, and it is VERY susceptible to osmotic changes resulting from salinity swings, often leading to membrane rupture and potential specimen loss. We see this most often in poorly shipped Linckia spp., however, this also accounts for the high rate of losses when shipping Blue Tuxedo urchins and the like (Mespilla spp.)

photo courtesy reefs.org library

Urchins do have some inter-tidal species that can withstand these swings much better than others, however, given enough change, (especially to hyposaline environments) they will die.


HTH

[Loverotties]

Cool! And yummy!

[PHIL GUY]

Originally Posted by dobejazz

I don't even want to know why you know how they taste

YOU CAN ASK A WOLF EEL HOW THEY TASTE

[themissinglynk]

I love this guy's articles...

http://www.reefkeeping.com/issues/2003-11/rs/index.php

This one is a nice article on urchins, and at the bottom of the article, is a nice table that describes the "good and bad" (and specifically what kind of reef things they might eat).

Hope it helps!