Arrow crab died after 4 months

[Bugenar]

We got an Arrow crab about 4 months ago. It was the model citizen for our tank, it never harmed anything, it was totally peaceful. We added a Diamondback goby a couple weeks ago, all it’s been doing is digging massive holes into my sand spiking the nutrient levels. During the goby digging its holes and clouding up my entire tank, the arrow crab slowed down.. started sitting in a corner all day. It ate for sure, but yesterday it just stopped moving. It was alive, but completely lethargic. I wish we had taken it out right then and there, maybe we could’ve saved it.

I think the cause of death was this goby, unless Arrow crabs naturally live for 4 months. This goby is making huge voids beneath my rocks, just spewing out whatever’s been in there for 10+ years. We should’ve done our research, this was bound to happen. But the damage is done; I want nothing more than to kill this goby. It’s done nothing but cause problems, but I know it’s wrong so we’re going to try and catch it. The sad thing is it has so many little hiding holes catching it will be nearly impossible, and because it dug holes under our rocks, we need to take the whole tank apart because the whole it’s unstable now. Everything.

The Arrow crab was our first invert. It’s seen every moment of this tanks upbringing, it survived a terrible aiptasia invasion, it survived a botched molt and rejuvenating it back to full strength was an amazing feeling. It really sucks that it died, the thought of it ever dying never occurred to me.

I’m going to post my levels in the comments, it’s not looking good… But I don't know how to stabilize it if this goby just undoes everything I do.

I don’t know if I should take its body out of the tank either, the CUC is doing their job… But looking at the body is so heartbreaking I don’t even want to touch it, let alone flush it down a toilet.

The Diamondback goby was absolutely the worst thing we’ve ever done for this tank, we ruined it by adding one thing.

 

[strich]

Really sorry about your loss mate! Arrow crabs are one of the coolest inverts around. :(

I do believe they can struggle with sudden water quality changes so you may be right about the cause of death. But don't be too hard on yourself (or the poor goby) - That's a tough scenario you found yourself in!

If you've had that sandbed in there for 10+ years as you say, and have never had a CUC to stir it up then yeah that's gonna be trouble.

Whats you plan now? You could let the goby do his thing and just make sure to really ramp up carbon filtering and water changes for awhile. But I don't know what kind of other life you have in the tank.

 

[Bugenar]

Really sorry about your loss mate! Arrow crabs are one of the coolest inverts around. :(

I do believe they can struggle with sudden water quality changes so you may be right about the cause of death. But don't be too hard on yourself (or the poor goby) - That's a tough scenario you found yourself in!

If you've had that sandbed in there for 10+ years as you say, and have never had a CUC to stir it up then yeah that's gonna be trouble.

Whats you plan now? You could let the goby do his thing and just make sure to really ramp up carbon filtering and water changes for awhile. But I don't know what kind of other life you have in the tank.

The goby will be fine, one way or another it’s getting out of the tank. It’s pouring sand all over my corals close to the bed and it already buried my mushroom. These are easy fixes if it weren’t for the fact it’s making tunnels everywhere… Our rocks are sitting on the sand and not deep enough to touch the glass…

This was a really stupid decision on our part and you’re right the fact the sand bed was so old and we got something that will rework the entire sand bed was a recipe for disaster.

Emotions aside, it’s hard to get mad at the goby for just doing what it was born to do. These sell out quickly at LFS so I’m sure someone will pick it up.

As for reworking the whole tank, we really need to see the damage done. In the pic I attached the whole middle section is the gobys home. It’s burrowed deep beneath that rock in the middle, possibly meaning there’s a huge hole in the middle of our rock work (not sealed together!). The safest option is to just do a reset of the rocks and level the sand out again, then reassemble the rocks, with epoxy, and rebuild everything.

Despite whatever the goby is doing tho.. everything is open.

 

[strich]

Tough decision to make re setting the rocks - you'd effectively have to rehome the whole tank and restart due to the sudden release of so much sentiment by touching all the sand.

I'd be tempted to try something much more surgical first like trying to force resettle the rock as it lies. But I dunno.