Thoughts on unnexplained (and very sad) die-off

[jostafew]

Hello everyone, I'm very sad to say it but it looks like I'm about to lose the last of my 4 fish, some of which I've had for nearly two years. It all started in the summer time, I noticed that I'd lost a couple inverts (cleaner shrimp, tuxedo urchin).

After investigating I found that the SG in my mixed reef had dropped to 1.021. Long period of water changes combined with the assumption that my salt mix was the same potency as previous batches. Over a period of a couple weeks I brought that back up to 1.025 and thought I'd caught it before things got too bad. But, things continued to deteriorate. I lost the other cleaner shrimp, a brittle star, and my bigger pincushion urchin. It was around this time that I was busy and not keeping up with tank maintenance as well as I should have, and missing inverts decomposing (especially that bigger urchin) dumped a pile of nutrients into the water causing a huge algae bloom. A month or two later my Kole tang began swimming eratically, upside down, and a day later died. Very sad day. Somewhere around this time my Fire shrimp died, too. Maybe a couple weeks later my otherwise healthy and hungry Pajama Cardinal appeared dead one morning, no warning signs whatsoever. No external signs of trouble on either of them.

Through all this my treasured Crocea clam was looking strong, and I was happy about that. Fast forward to about two months ago. My clam started to decline. I'd always been concerned that it was receiving insufficient light, so I moved it from the sand-bed up the rock-work. Things stayed the same, continued to slowly decline. About a month ago I noticed that my Black clown had begun looking very thin. I'd always suspected that it had internal parasites as I would sometimes see stringy poop, but it always ate well and looked otherwise healthy. At this point I didn't have much left to lose in my reef so I dosed the system with Prazipro. Followed by a 2nd dose 6 days later. Sometime in the last couple weeks I noticed that my Azure Damsel was breathing heavily, like it would if oxygenation were a problem in the tank. Didn't see how that could be possible though considering I run the DT topless and the temperature was the same 79deg. it always was.

Finally last week during renovations in the house I tore down the old tank and began building the new. The remaining two fish, very sad looking clam, and one larger hermit crab (only remaining livestock aside from the corals) went into a temporary tank while the build happened. They stayed there for three days. During that time the Damsel died and the clown stopped eating, and the clam died.

Now, the new system has been running since Tuesday with live rock, sand, and half of its water from the old system. Livestock consists of coral, a nearly dead hermit crab, and a clown which is still not eating and I expect to die at any moment.

Along the way the only thing I found wrong in the water params were Mag and Calcium reading higher than usual, and Alk low (about 6.2dkh). I started to correct the Alk slowly, but nothing too crazy.

So, very hard to see all those creatures die under my care, especially considering that I don't know what happened... The damsel and the clown I've had for nearly two years, the Tang I'd had for about 6 months, and the pajama cardinal I had for probably two or three. It was the last thing into the tank, but it was quarantined and showed no signs of illness during QT or after being introduced to the DT. Most of the inverts were a year or two old as well. The invert die off I'm attributing to the intial low SG and a cascade effect of dieoff and poor water quality, but the fish are hardly delicate species and seem to be dying from some illness with no visible symptoms and does not respond to prazipro.

At this point the tank will stay fishless for a good two months. If there was some disease in there I want to give it time to dissipate before re-introducing any fish. I did plan to try a couple new cleaner shrimp just for some movement now that the params are stable though... Any thoughts on what might have happened and/or best way to proceed so as to avoid a recurrence?

[gregzz4]

Sorry to read about your losses

Sounds like a cascade effect
Low Sg starts killing inverts and other sensitive life, ammo levels start to rise, bacteria starts to die off faster, more ammo, fish who are OK fighting off whatever is present in good water start to succumb to things their lowered immune systems can no longer deal with
Add the Prazipro and possibly this was the final straw

Prazipro can raise pH. Ammonia from die-off combined with higher pH can be lethal at much lower levels than our target pH would normally allow us to get away with

Just my thoughts

As far as proceeding goes, have you been testing for a cycle ?

[jostafew]

Thanks for the feedback gregzz, I've done a couple ammonia tests before and during the transition but they've always come up with nothing. I've also got one of those ammonia monitor things in the tank now to watch for any remaining issues but it has always read zero as well. To be honest I don't expect to see a cycle in the new system as it's 50% new water, all of the rock and sand was from a mature system, and all of the LR was scrubbed pretty vigorously (in tankwater) to remove any of the pest algae that had previously developed. But I have nitrite and nitrate test kits as well and will do a few tests here and there to watch for any changes over the next week or so.

[kien]

Sorry to hear if your loss. The hobby is hard enough as it is but to loose your tank inhabitants like that is a real kick to the nads :-(. Been there.. :-(

When you treated your tank with prazi pro did you turn off your skimmer like the bottle suggests? If I recall correctly the instructions say that you should turn off your skimmer. This is likely due to the fact that your skimmer could skim out the meds making it less effective. HOWEVER, I personally would not recommend doing this as turning off your skimmer for a period of time can dramatically reduce the oxygen in your tank. Mind you, if you don't have a skimmer then this is a non issue.

My recommendation when using meds with a skimmer is always to take off the skimmer cup and let it overflow into your sump during the treatment period. Assuming you have a sump of course.

[howdy20012002]

sorry for your losses..it always sucks when you lose things unexpectedly or for no apparent reason.
to be honest, I don't think that the SG at 1.021 would have killed the inverts if it had been a gradual reduction.
I would look elsewhere for the cause personally.
I am not sure what to suggest beyond that.
good luck
Neal

[Madreefer]

Originally Posted by howdy20012002

sorry for your losses..it always sucks when you lose things unexpectedly or for no apparent reason.
to be honest, I don't think that the SG at 1.021 would have killed the inverts if it had been a gradual reduction.
I would look elsewhere for the cause personally.
I am not sure what to suggest beyond that.
good luck
Neal

I totally agree with you and hoping someone else would respond first. I had a debate with another member about SG last week. Most stores keep their sg at 1.021.

[jostafew]

Thanks for the feedback guys. Neal, that's a good suggestion about keeping the skimmer running but taking out the cup. I did turn it off for the 12 days during treatment as recomended, but you're right I could have left it running (though not functioning) for oxygenation.

As for the SG decrease, yes it would have been very gradual, over the course of several months.

[albert_dao]

So... Were you using Reef Crystals?

[jostafew]

Nope, was using IO. Same as I had been since day one. Odd thing though, this batch had a much finer consistency than the previous buckets and I learned the hard way that it mixes up with a lower SG than usual.

[gregzz4]

Originally Posted by Madreefer

I had a debate with another member about SG

Me
I only mentioned the Sg possibility as the OP stated he lost inverts first, and I'll agree a gradual drop most likely was not the cause

I'm sure there's something out there, but I'm not aware of an infection that kills both fish and inverts. Maybe someone else knows ?
I say this as it still sounds to me like some kind of exposure or contamination

Do you remember using anything last summer that you'd not previously used ?