How many urchins are too many?

[BrettDS]

I got quite a few urchin hitchhikers with my live rock and live sand. One large light purple one came in with the live sand (he's a good 2.5 - 3 inches across). I also have on the order of 12 to 14 deep purple or black ones that came in with the live rock. They started out pretty small, but have been growing quite a bit since I got them. The largest few are probably 2.5 inches across, most are 1.5-2 inches and there are a couple between 1 and 1.5 inches. They are in a 75G display tank.



I suppose the fact that they keep growing is probably a good sign, but I wouldn't want them to starve or anything, so I'm wondering if I should take a few into my LFS or trade them with someone else.



Do you guys think my 75G tank can support 14 or 15 decently sized urchins or would I be better off sending a few on to other homes?

 

[Betta132]

I'd suggest either feeding them with dried nori or getting rid of some. See if you can find somebody who wants them in trade, you can probably get something for them.

 

[BrettDS]

Thanks. I've put nori in on a clip for my tang, but I've never seen a single urchin go for it. Maybe I'll try to put some next to one of the urchins and see how that goes.

On a side note, apparently I was wrong about the number. My wife and I counted 15 of the deep purple/black ones this morning. And I still suspect there are a few more behind the rocks that we couldn't see. I'm beginning to wonder if they are reproducing because I don't think we had that many to start with.

 

[owen386]

Thats wild. But yeah will definitely need to supplement with something, less your tank is filled with algae

 

[QuiGonJay]

They are eating machines. You'll likely need to bring some in to the LFS or they may starve. They are quite adept at hiding in rocks and quite small. I've had them appear seemingly out of nowhere on the rock and grow from the size of bb pellet to a golf ball in about 6 months. They are amazing little creatures.

 

[QuiGonJay]

I tried the nori route too and the urchins never seemed interested. Just the hermits.

 

[gnasher]

Where did you get those rocks? :eek1:

 

[BrettDS]

Where did you get those rocks? :eek1:

Tampa Bay Saltwater. They are great rocks and came with a lot of stuff (including a ton of urchins). I highly recommend them.

 

[Shawn O]

If you can find a happy medium between not enough algae and too much algae you could have a real nice Urchin tank. Probably easier to find them homes. If your friends or your LFS don't want them, Craigslist would probably move them pretty quick.