Sea Urchin survival

[Magellan]

I posted about this guy a while back, my poor Urchin had an injury a couple months ago (he had moved when I was scraping the glass and i accidentally poked him with the hard plastic corner of the scraper). Initially the only evidence was a tiny scrape, but gradually that got worse and worse and so did his condition. He lost a lot of spines and I considered putting him in the freezer at one point, but ultimately he recovered and has been active and eating over the past few weeks. He loves to pick things up and camouflage himself, so I haven’t been able to see the wound site for a while. Today I realized that he has an actual hole in his shell. Is this permanent? If so will he be fine? I took the pics today, he moves a good bit when he wants to.

 

[P-Dub]

Wholey mackerel. I would have said he's a goner for sure but, alas, he's alive. Unbelievable! Couldn't say if it's permanent or if it will ultimately survive but I'm amazed.

 

[Magellan]

Wholey mackerel. I would have said he's a goner for sure but, alas, he's alive. Unbelievable! Couldn't say if it's permanent or if it will ultimately survive but I'm amazed.

As recently as a few days ago the hole wasn’t there, just an ugly dark red spot with no spines. It’s as if that spot on his exoskeleton has just slowly rotted away...For comparison, heres an old photo from May 17th (didn’t realize it had been that long, I’ve even changed the lights since then!) He had already mostly recovered at that point and was moving around and eating. Now I would say his behavior is completely normal and has been for a long time...other than the fact that I can see his insides!

 

[Magellan]

Woke up today and he was upside down with a hermit crab poking at him. It appears that no, sea urchins can not survive with holes in them. (In fairness to the scientific method, he had also decided to crawl directly across a stubborn spot of cyano on my sandbed yesterday, but Occam’s Razor would suggest the hole in his shell was more relevant to his demise).

He tried his best :/

 

[P-Dub]

Not surprised but still amazed. It's a bummer.

 

[Magellan]

Not surprised but still amazed. It's a bummer.

he was one of the first things I put in the tank when it finished its cycle about 6 months ago (it’s been a learning experience!). I’ve lost a couple of snails to murderous hermit crabs but the urchin was my first death :/

 

[Bananas for the Soul]

I know this is an old post, but I can’t find too much on the issue. Kiwi, my blue tuxedo urchin, has a very similar hole in him, almost the same location, even. Last night, I was trying to get rid of some algae on a rock and took it out to scrub it outside of the main tank. I didn’t realize Kiwi was even on it until I stepped on him. He must have been out of the water for a good five minutes before I stepped on him. I have no idea how, but I didn’t completely crush him. I immediately burst into tears; I’ve had him for a little over three years and he was one of my firsts, as well. When I first put him in, all he would do was float. I held him down and let the air bubbles escape, then I put him next to some rocks and corals hoping he’d grab hold. Thankfully, he did! He was immediately making his way around things, maneuvering himself to a hood position for a few good photos of his injury. I honestly didn’t think he’d make it through the night.

I was scared to check on him before leaving for school (I teach kindergarten) because if he was dead, I would have fallen apart and had to remove him, do a water change if the ammonia was spiking, etc. I know I was a big stupid to risk everyone and everything, but I just couldn’t bear to look. Once I got home, one of the first things I did was check on him. He’s still alive! I’m praying he stays that way, but the original urchin in this post has kinda given me a bleak outlook on him. I can’t even imagine the horror of finding him being eaten by the crabs!

Has anyone else had an experience like these two guys? What’s the prognosis? Does he even stand a chance? Is there anything I can do to help him? I’m at a complete loss! He, Potato (my pistol shrimp), and Banana (yellow wm goby) are the sole survivors from my initial tank three years ago. I had a major infestation of fire worms and decided to just upgrade to a larger tank (13.5 gallon to 32.5 gallon) as opposed to trying to fix the issue and lost a few in the transition. It was a hard loss, so Kiwi just can’t die! He just can’t. Any advice, be it good or bad, is welcome. I just want to be prepared mentally for the worst.

 

[ISpeakForTheSeas]

Has anyone else had an experience like these two guys? What’s the prognosis? Does he even stand a chance? Is there anything I can do to help him?

Hopefully someone with hands-on experience will chime in for you here, but I wouldn't give up hope. If it has survived this long, your water quality must be alright for it, so I'd guess there's a fair chance it'll recover:

Severely damaged sea urchin shows astonishing resilience

Together with his colleague Christian Neumann of the Natural History Museum in Berlin, Senckenberg scientist Max Wisshak documented a sea urchin's fight for survival on the ocean floor off Spitsbergen. In their study, recently published in the scientific journal Polar Biology, the researchers...

phys.org