Help with a black urchin

I tested about 10 days prior (so 3 weeks ago), it was fine 1.024, did the water change, then retested the tank at 1 week after the water change and it was low, so 2 weeks probably.

 

Okay- got a shot of the urchin-
http://i37.photobucket.com/albums/e99/bbsbliss/urchinsick.jpg

 

Salinity should be kept at a 1.023 minimum, if your's dropped that much after a water change, just wondering did you add salt to the new water?
The black sea urchin eats coraline algae aswell as green, mine leaves white trails in its path, poor quality will make the spines fall out, very doubtfull its being bullied by a fish.
You need to get the water spot on, concentrate on doing this and see how he goes, in the meantime supplement his diet till he perks up...Hopes this helps...

 

are you testing with a swing arm hydrometer or a refractometer?

If you're at 1.019 with a refractometer you need to work on getting it up to 1.023-1.026 asap over the next couple of days, topoff with salt and do some small water changes with higher sg water to get it up

 

it doesn't look that bad, I was expecting allot worse. I agree, need to bring salinity up to minimum of 1.023 but you also have to do it really slowly so you don't stress that poor pincushion any more than it is already.

If it does not look like he is eating the seaweed you can try some Pleco-tabs or the algae supplement tabs you feed to plecostomus's in fresh water tanks, mine love them.

There are some urchins that need salinity higher than 1.036 but most need it at 1.023 to 1.026, From what I read the purple urchin needs 1.030 to which I ask who wants a tank full of just urchins?

 

I've obsessed over this poor thing all night! Last night I added water to the sump ( 48 hour old, new Instant Ocean, with conditioner- tested before I put it in, salinity was 1.024, temp 78). I put a sheet of nori under a rock right by his hiding spot, last night before lights out. This am, did ALL chemistry again, salt was up to 1.024, all other numbers came out fine. He has moved to the sand, his spines are waving, and the nori is gone. I'm hoping this is the turnaround. I'll keep up with the nori sheets and watch my numbers daily, maybe this will turn out okay! Thanks for all the input- I'm very new to the hobby, and the tank was given to me from a friend moving out of state, so I wasn't looking for this ( I've never even had goldfish!)- but now I'm hooked and want to do a good job!

 

Keep up the good work! with urchins you really have to watch the salinity sways. I am glad he is doing better. If I am feeding the nori I have a rock I attach it to with a rubber band then I drop it right in front of them his way it can not float away from them.

 

Hope all works out...

 

moving and eating is a good sign. best of luck with this guy and watch out for the stickers taht are left, a buddy of mine got one shot under his thumbnail by his long spine wasn't a fun trip to the ER

 

Just an update- the urchin died tonight. The hermit crab was starting to dismantle him, so I pulled the urchin out. This whole "circle of life" thing is a little depressing at times!