Introduction and Black Spiny Sea Urchin Problems

sequential · 01/29/2006, 01:09 AM

Good morning. Please excuse the lengthy introduction for such a short question, but I feel it's important to share the backstory to understand the problem.

Two years ago, I began a marine aquarium. Unfortunately, in those two years, the only advice I have received has been from friends who have freshwater tanks and local vendors that sell me my fish and supplies. If it weren't for a great deal of patience and luck, I think this could have been a recipe for disaster. Slowly, however, I have learned enough to consider myself new to the hobby with a very stable tank.

Until today, I had a single 38 (possibly 37?) gallon, 30" wide tank. It has significant amount of live rock - enough to pile to within six inches of the top and have a stable base. Quite ignorantly, I trusted the advice of a friend who exclaimed my live sand was causing my red slime problem. The result is that I now have small pebbles at the bottom.

The tank contains two, approximately six inch long neon gobies, but I've never seen a pair like them since I purchased them. They are black and white and have snake or zebra like, vertical stripes. They are aggressive builders, terribly shy, and extremely lovable. They've been in the tank from shortly after the tank cycled. The pebbles at the bottom are small enough for the two of them to move around and they never seem to tire of doing so, much to my delight.

Another survivor of the process of stabiliziing the tank is the clown fish. He's about twice the size of the largest damsels in the tank. Since the introduction of damsels more recently, he's become extremely aggressive to the smaller, faster damsels. He doesn't appear to bite them, but he did have his way with some dwarf puffers. When he's not chasing the damsels, he's fascinating to watch with the tanks only anemone. The anemone is the single largest inhabitant of the tank. He's quite healthy. He hasn't moved his foot since I rebuilt the tank after a move. He's grown from smaller than a handful to wider than nine inches across when outstretched. He has a healthy appetite and is a good neighbor to most of the other inhabitants.

That is, with one exception. I purchased a black spiny urcin to help maintain my macro algae. The urchin made quick work of the algae and developed a healthy appetite for romane lettuce. Needless to say, the cute little ball of soot became quite large. His longest spines are about 8 inches long. When he's hanging out on the front of the tank, he spreads to about 15 inches. He's the reason I abandoned my original 20 gallon wide tank. Originally I had hoped he'd drop his spines in the small tank, but he became aggressive to the tube worm in the tank, eating the crown and much of the tube before I could rescue it. The tube worm survived, but remained in hiding for the better part of ten days.

In the 38 tall, the urchin grew to his present size. When I stopped feeding him romain, he began aggressively feeding on all surfaces of the tank. He has been the same size for a few months now, but with the anemone outgrowing him, the two regularly were aggressive to each other. The two would spend hours a day dancing around each other. Every morning, when the tank light goes on, the urchin would be sitting inches above the anemone, poking at it with its many spines. When the anemone expanded to the light, the urchin would retreat.

Suddenly, about two weeks ago, two damsels went missing shortly after a water change. The anemone never produced bones or even looked like he had consumed the fish. In fact, the bones have yet to be found. A couple of days later, we found the urchin on top of the tube worm, with a length wise hole in the tube and the worm missing. The crown of the worm had long since recovered from the first attack and appeared to split into two separate crowns, but now the worm is gone. Hopefully, he's in hiding, I haven't given up.

Considering the effort that went into stablizing the tank, this aggression and death has been quite sad. So, I revived the 20 gallon wide, filled it with three or so inches of live sand, and moved the urchin. He's eating dried seaweed, and has plenty of room to stretch or roam. The problem is, there is nothing else in the tank with it. Given his size, I'm hesitant to add large live rock, though I am keeping my eyes open for unusually flat live rock to create some walls he can feed on.

With all of that back story, here's my question: without moving to a larger tank, what would you recommend I do with the urchin in the 20 gallon wide? Does the black spiny urchin have preferences that I can address with light, algae, companions, or feeding? I'm working on growing a variety of macro algae in the 38 gallon tall tank to feed the urchin, but it will take a while before it all takes, if it does. Any suggestions would be welcome. Thanks.

bertoni · 01/29/2006, 01:22 AM

To Reef Central

Hmm, they aren't neon gobies, at least not the species I have heard named that way. Is this the fish?

http://www.wetwebmedia.com/pholodichthyidae.htm

It's not uncommon for an urchin to go after some animal for food. Seems to be a part of their diet. The invertebrate forum will have more. Sounds like you need to trade the animal in, IMO. The 38g is pretty small for it.

The anemone might have gotten the damsels. That would be my guess. Bones can be digested, so I wouldn't necessarily expect to see any.

sequential · 01/29/2006, 01:35 AM

Quote:

Hmm, they aren't neon gobies, at least not the species I have heard named that way. Is this the fish?

http://www.wetwebmedia.com/pholodichthyidae.htm

The bottom picture is as close as I've seen in two years. :-)

Quote:

It's not uncommon for an urchin to go after some animal for food. Seems to be a part of their diet. The invertebrate forum will have more. Sounds like you need to trade the animal in, IMO. The 38g is pretty small for it.

Right now he's isolated in a 20g wide. He seems to be okay, with lots of room, but I can't imagine this is sustainable without some live rock. At the very least, it's very empty looking to those in the house that watch the tanks. Maybe I'm over thinking it right now. As much as I want to keep the urchin, the last thing I'd want is to see him sick or worse.

At the moment, he's being hand fed and receiving lots of observation. If he shows any signs of stress or deterioration, we have arranged for a local aquarium to host him for a few months while we plan a tank upgrade.

Quote:

The anemone might have gotten the damsels. That would be my guess. Bones can be digested, so I wouldn't necessarily expect to see any.

Good to know. I was under the impression I'd find bones. Thank you for the welcome and your thoughts.

sequential · 01/29/2006, 10:16 AM

After looking around the web for a bit, I've come to the conclusion that the urchin is in fact a Diadema setosum, not a Centrostephanus rodgersii. The size of the spines just makes a lot more sense, not to mention, it looks exactly like the urchin pictured here.

Considering the seller of the urchin was convinced he was selling me a "black spiny sea urchin" and I ended up with a black "longspine urchin", I think the source of confusion was a benign game of telephone between wholesaler and vendor or between vendor and customer. :-)

Yay!

bertoni · 01/29/2006, 12:27 PM

As long as the urchin gets fed well, it'll probably be fine in that tank. You might throw in a bit of seafood now and then and see how it goes.

01/29/2006, 01:09 AM	#1
sequential Registered Member Join Date: Jan 2006 Location: Connecticut Posts: 266	Introduction and Black Spiny Sea Urchin Problems Good morning. Please excuse the lengthy introduction for such a short question, but I feel it's important to share the backstory to understand the problem. Two years ago, I began a marine aquarium. Unfortunately, in those two years, the only advice I have received has been from friends who have freshwater tanks and local vendors that sell me my fish and supplies. If it weren't for a great deal of patience and luck, I think this could have been a recipe for disaster. Slowly, however, I have learned enough to consider myself new to the hobby with a very stable tank. Until today, I had a single 38 (possibly 37?) gallon, 30" wide tank. It has significant amount of live rock - enough to pile to within six inches of the top and have a stable base. Quite ignorantly, I trusted the advice of a friend who exclaimed my live sand was causing my red slime problem. The result is that I now have small pebbles at the bottom. The tank contains two, approximately six inch long neon gobies, but I've never seen a pair like them since I purchased them. They are black and white and have snake or zebra like, vertical stripes. They are aggressive builders, terribly shy, and extremely lovable. They've been in the tank from shortly after the tank cycled. The pebbles at the bottom are small enough for the two of them to move around and they never seem to tire of doing so, much to my delight. Another survivor of the process of stabiliziing the tank is the clown fish. He's about twice the size of the largest damsels in the tank. Since the introduction of damsels more recently, he's become extremely aggressive to the smaller, faster damsels. He doesn't appear to bite them, but he did have his way with some dwarf puffers. When he's not chasing the damsels, he's fascinating to watch with the tanks only anemone. The anemone is the single largest inhabitant of the tank. He's quite healthy. He hasn't moved his foot since I rebuilt the tank after a move. He's grown from smaller than a handful to wider than nine inches across when outstretched. He has a healthy appetite and is a good neighbor to most of the other inhabitants. That is, with one exception. I purchased a black spiny urcin to help maintain my macro algae. The urchin made quick work of the algae and developed a healthy appetite for romane lettuce. Needless to say, the cute little ball of soot became quite large. His longest spines are about 8 inches long. When he's hanging out on the front of the tank, he spreads to about 15 inches. He's the reason I abandoned my original 20 gallon wide tank. Originally I had hoped he'd drop his spines in the small tank, but he became aggressive to the tube worm in the tank, eating the crown and much of the tube before I could rescue it. The tube worm survived, but remained in hiding for the better part of ten days. In the 38 tall, the urchin grew to his present size. When I stopped feeding him romain, he began aggressively feeding on all surfaces of the tank. He has been the same size for a few months now, but with the anemone outgrowing him, the two regularly were aggressive to each other. The two would spend hours a day dancing around each other. Every morning, when the tank light goes on, the urchin would be sitting inches above the anemone, poking at it with its many spines. When the anemone expanded to the light, the urchin would retreat. Suddenly, about two weeks ago, two damsels went missing shortly after a water change. The anemone never produced bones or even looked like he had consumed the fish. In fact, the bones have yet to be found. A couple of days later, we found the urchin on top of the tube worm, with a length wise hole in the tube and the worm missing. The crown of the worm had long since recovered from the first attack and appeared to split into two separate crowns, but now the worm is gone. Hopefully, he's in hiding, I haven't given up. Considering the effort that went into stablizing the tank, this aggression and death has been quite sad. So, I revived the 20 gallon wide, filled it with three or so inches of live sand, and moved the urchin. He's eating dried seaweed, and has plenty of room to stretch or roam. The problem is, there is nothing else in the tank with it. Given his size, I'm hesitant to add large live rock, though I am keeping my eyes open for unusually flat live rock to create some walls he can feed on. With all of that back story, here's my question: without moving to a larger tank, what would you recommend I do with the urchin in the 20 gallon wide? Does the black spiny urchin have preferences that I can address with light, algae, companions, or feeding? I'm working on growing a variety of macro algae in the 38 gallon tall tank to feed the urchin, but it will take a while before it all takes, if it does. Any suggestions would be welcome. Thanks.

01/29/2006, 01:22 AM	#2
bertoni RC Mod Join Date: Mar 2002 Location: Mountain View, CA, USA Posts: 88,616	*To Reef Central* Hmm, they aren't neon gobies, at least not the species I have heard named that way. Is this the fish? http://www.wetwebmedia.com/pholodichthyidae.htm It's not uncommon for an urchin to go after some animal for food. Seems to be a part of their diet. The invertebrate forum will have more. Sounds like you need to trade the animal in, IMO. The 38g is pretty small for it. The anemone might have gotten the damsels. That would be my guess. Bones can be digested, so I wouldn't necessarily expect to see any. __________________ Jonathan Bertoni

01/29/2006, 10:16 AM	#4
sequential Registered Member Join Date: Jan 2006 Location: Connecticut Posts: 266	Not a black spiny sea urchin after all. After looking around the web for a bit, I've come to the conclusion that the urchin is in fact a Diadema setosum, not a Centrostephanus rodgersii. The size of the spines just makes a lot more sense, not to mention, it looks exactly like the urchin pictured here. Considering the seller of the urchin was convinced he was selling me a "black spiny sea urchin" and I ended up with a black "longspine urchin", I think the source of confusion was a benign game of telephone between wholesaler and vendor or between vendor and customer. :-) Yay!

01/29/2006, 12:27 PM	#5
bertoni RC Mod Join Date: Mar 2002 Location: Mountain View, CA, USA Posts: 88,616	As long as the urchin gets fed well, it'll probably be fine in that tank. You might throw in a bit of seafood now and then and see how it goes. __________________ Jonathan Bertoni