Sherlock Holmes anyone ?

[Buccaneer]

Ok ... here is what happened so far ...
had a nuisance algae on sandbed so wife and I decided to vacuum it off ...
mixed up 30 Gallons of water to replace the siphoned water and went to work ...
in vacuuming I got a little too close to my LTA and " cleaned " a few tentacles by accident ... he seemed OK and today is just fine ( this was last nite )
siphoned sand was cleaned and returned to tank
almost finished returning sand to tank and noticed the green chromis acting weird and panting ... within minutes all five were dead
then my firefish ... same thing ... gone
then my shrimp ... 4 cleaners / 2 peppermint and a Coral banded shrimp ( had the CBS for 4 years )

My CBB , Foxface, Sailfin Blenny and Yellow Tang are all fine

Tested Nitrite / Nitrate / ammonia ... all zero
PH 8.2
temp 82
SG 1.025

Now the potential problems ...
Tiger Tail cuke ... have not seen him but that is not unusual as he can go hiding in the rocks for days at a time ... also supposedly non-lethal cuke ?
Foxface ... venomous but why pick on 5 GC and all the shrimp ?
Refugium ... maybe a macro went asexual ??? ... read somewhere on RC that it can be toxic if it happens ???
siphoned too deep ? ... maybe I siphoned too deep but would'nt it show up on the tests ?
LTA ... does not give off a poison of any kind does it ?


If anyone has any ideas then let me know

Cheers

[Aquattro]

Did they start acting funny as you put the sand back? Maybe something in the bucket you were cleaning the sand in? To wipe out that much that quickly, it has to be something really nasty. I don't think algae going sexual would do that, and you'd see it in the water.
Siphoning too deep wouldn't do it. I would imagine that if the cuke "exploded", it would take out all or nothing.
LTA, not likely, same with the foxface.

[MalHavoc]

If some macro had gone sexual, you would have noticed it in a big way, since it's usually accompanied by your tank water getting quite cloudy. How deep did you siphon your sand bed? Siphoning a working DSB is usually a 'bad thing' because it can disturb the stratification that occurs and can kill off some of the bacteria that live deeper down, resulting in a lowered ability to process nutrient.

I'd try to find that cuke. All cukes are toxic to some degree. The less brighly coloured ones seem less toxic, but DGenR8, a mod over on RC, attributes a mysterious tank crash that wiped out all his fish a few years ago, to a missing black cucumber. Something to think about.

It's possible that the LTA poisoned your fish. Anemones that are dying in a can do terrible things to a reef tank. I know you said that it looks fine, but I'd watch it very carefully over the next day or so. Perhaps do a water change as well. If it looks fine, though, it's probably not what caused stuff.

Have you measured your ORP? I'd be interested in knowing if it dropped over the last 24 hours or so. That may be an indicator of something going awry.

Sorry to hear about the loss

[Buccaneer]

I guess it is " possible " that the bucket had something in it ??? been using these buckets for some time tho so unlikely but you never know.

I only siphoned about 25% - 30% of the sandbed ... I also have a sump and a refugium witha DSB and about 450 LBS of Live Rock so there should be enough left to handle a relatively low bioload

I checked the pods/bristle worms/bristle stars in the tank / sump / refugium and all are OK so whatever got my shrimp / fish had to dissapate rather quickly and also why did it not affect the other fish ?

Is there anything in the sandbed that could be toxic that I have not tested for ? ( dont have a test for orp )

Thanks for the ideas so far

Cheers

[EmilyB]

I have siphon/cleaned all the sand bed I can reach in my tank. The bed was four years old and quite compressed, as well I was having an algae problem on the bed.

I did not remove sand tho, I think that would stir up way too much crud. I just used a python, and then poke a section, slowly let the brown dirt rise to the top, and the clean sand fall back down. With just a gravity siphon even the worms drop back to the bottom.

BTW, my LTA is very shy. I can vacuum all around the sebae and it could care less about my prodding, but if I touch the LTA, it reacts like I'm trying to kill the poor thing.

[Buccaneer]

Originally Posted by EmilyB

BTW, my LTA is very shy.

but if I touch the LTA, it reacts like I'm trying to kill the poor thing.

Thats what happened to mine too ! ... I could almost hear it scream LOL

Cheers

[Buccaneer]

Ok ... the worm has been found ! ( Tiger Tail Cuke ) ... so that eliminates one more thing ... the caulerpa looks a little bleached tho ... but no cloudy water at all ?

Cheers

[Canadian Man]

One of my chromis dissapeared yesterday. No explanation and no help but maybe this is the time of year that some sea creatures decide to "just die"

[EmilyB]

ah...no...but nice try Jon

[Van down by the river]

I'm going to go with poisoning....not from the Cuke.(obviously as he's alive)
When a cucumber goes, I agree it's all or nothing. The anemone appears fine, if it was decaying that's another story but it's not.

Could it have stung them? maybe, but many inverts are quite tolerant of anemone stings so I would suspect your other fish would go first. Mind you this is a possibility as firefish are scaleless, and Chromis can be delicate. But then your sailfin blenny should have been affected too.

When you were vacuuming did you pull up any smelly (blackish)spots aka: sulphur dioxide? It is a small possibility that you released this into the tank which would have caused the heavy breathing ( but so would released nematocysts).Your circulation would have dissipated it fairly quickly and the larger hardier fish may have been able to tolerate the diluted amounts.

I think that the dramatic changing of sand and 30 gallon water change are most likely the causing culprit. I don't know the full size of your tank but 30gal water change of new water and the stirring of the sand bed could have caused low oxygen levels as well.
I think you will never really know which it was or maybe a combination of some or all of these possibilities.