question on Urchins

dethsight

dethsight

Member
i have 3 urchins in my new 150 gallon, all brought over from my 55G tank. there are 2 pencil urchins (one pretty small and one with a body diameter of about a golf ball, except flatter on top and bottom) and a white pin cushion urchin. i watched them closely in the 55G tank just to see what all they would eat. the white pin cushion seemed to love the coraline algae on the glass. u could always tell where he had been due to the pattern or the coraline. the bigger pencil urchin loves to cruse around on the rocks and strip quite a bit of coraline off them. the small pencil urchin is almost always inside some rock crevices, presumably eating w/e is there (possibly small feather dusters? which i have hundreds of.)
question is this: is coraline all they eat or are they just eating it cause its readily available?
 
flower

flower

Well-Known Member
Quote:
Originally Posted by dethsight http:///forum/thread/386229/question-on-urchins#post_3391129
i have 3 urchins in my new 150 gallon, all brought over from my 55G tank. there are 2 pencil urchins (one pretty small and one with a body diameter of about a golf ball, except flatter on top and bottom) and a white pin cushion urchin. i watched them closely in the 55G tank just to see what all they would eat. the white pin cushion seemed to love the coraline algae on the glass. u could always tell where he had been due to the pattern or the coraline. the bigger pencil urchin loves to cruse around on the rocks and strip quite a bit of coraline off them. the small pencil urchin is almost always inside some rock crevices, presumably eating w/e is there (possibly small feather dusters? which i have hundreds of.)
question is this: is coraline all they eat or are they just eating it cause its readily available?
Hi,
I think they eat all algae. Three in a 55g may not be the best thing. They eat every shread of algae then starve. If start noticing them losing spikes they don't have enough food.
 
dethsight

dethsight

Member
Quote:
Originally Posted by Flower http:///forum/thread/386229/question-on-urchins#post_3391159
Hi,
I think they eat all algae. Three in a 55g may not be the best thing. They eat every shread of algae then starve. If start noticing them losing spikes they don't have enough food.
the only one i have seen lose spikes is the smallest one. but he has many longer spikes where the smaller ones were.
they are in a 150 now so they may have more to feast on once it starts getting coraline on the glass.
 
spanko

spanko

Active Member
From wetwebmedia.
"Eucidaris tribuloides (Lamarck 1816), Mine, Pencil, Club Urchin. Tropical West Atlantic. Solitary, hiding by day. Live on algae, bryozoans, sponges, tunicates in the wild. Algae and opened shellfish in captivity. To about three inches in diameter."
And if the white pin cushion is actually this.....
"Tripneustes depressus A. Agassiz 1863, the White Sea Urchin. To 12.5 inches in diameter. Eastern Pacific; Southern California to Ecuador and Galapagos Islands. Principally feeds on coralline algae."
 
flower

flower

Well-Known Member
Quote:
Originally Posted by dethsight http:///forum/thread/386229/question-on-urchins#post_3391163
the only one i have seen lose spikes is the smallest one. but he has many longer spikes where the smaller ones were.
they are in a 150 now so they may have more to feast on once it starts getting coraline on the glass.
I suppose it would be normal to lose a few here and there but if you can actually notice a loss, then it's starving. I bet pne urchin can keep a 180g clean. They are a bit of a bulldozer so make sure all is secure.
 
dethsight

dethsight

Member
Quote:
Originally Posted by Flower http:///forum/thread/386229/question-on-urchins#post_3391171
I suppose it would be normal to lose a few here and there but if you can actually notice a loss, then it's starving. I bet pne urchin can keep a 180g clean. They are a bit of a bulldozer so make sure all is secure.
for sure a bulldozer. the big one used to knock over my bridge rock at least once a week back in the 55gallon. lol. but, that's why i didn't have it stacked to the roof. and as of right now, theres not much he can really knock over. i say this now, but i bet by monday he will find something to move/shift around.
and that does sound like my white pin cushion urchin, Spanko. i think if he gets THAT big he may get to go back to the fish store. actually, the LFS owner told me he had a long spine black urchin a while back that got to be as big as a dinner plate! luckly, they are slow growers.
 
S

saxman

Guest
Diadema urchins don't grow THAT slowly. We had one that got HUGE in the space of a couple of years...so huge, I had to re-home it (it was in a 55 gal).
As for pencil urchins, they aren't as benign as many are led to believe. Ours was relegated to sump monkey status when it developed a taste for coral, and we've heard of other having the same issue.
HTH
 
flower

flower

Well-Known Member
Quote:
Originally Posted by saxman http:///forum/thread/386229/question-on-urchins#post_3391219
Diadema urchins don't grow THAT slowly. We had one that got HUGE in the space of a couple of years...so huge, I had to re-home it (it was in a 55 gal).
As for pencil urchins, they aren't as benign as many are led to believe. Ours was relegated to sump monkey status when it developed a taste for coral, and we've heard of other having the same issue.
HTH
+1 Mine got nealy double it's size and began to starve...they are crazy algae eaters, my 90g was covered in coraline and it striped the back and side glass bare in no time. I had hoped it would glean from one side then move on letting the rest grow again and keep him in algae but not even my tank could sustain it beyond a year. It was a totally cool critter while I had it.
 
dethsight

dethsight

Member
sounds like they are more of a "have them for a while to clean things up, then return to fish store" kinda creatures. which i am OK with. and i never thought of putting the bigger one in the sump. the sump doesnt have any lights on it so im pretty sure coraline wont grow...but i have thought of putting some of my smaller rocks at the bottom of the bio-ball area, where the water collects before going through the other filter and into the actual pump area. i would do some sort of refugium/sump combo if i had a way to get light down through the bio-balls.
 
dethsight

dethsight

Member
i have looked over my urchins this morning and haven't seen any missing spikes on them. so, the ones i see one the sand from time to time must just fall off and get replaced and/or be in the process of being "shed" in a sense.
 
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