Fish Dead, Corals affected, no obvious reason why...water quality or toxin release?

[Oldtimer]

Looking for some feedback on this one!

I came home from work 2 days ago to see that all of my fish except for the three chromis were not visible and that many of my corals (namely xenia, zoas and montis) had very little to no PE. The Xenia in particular were very shriveled up even more than they do normally at nighttime. Many of my acros has reduced PE as well. All snails, crabs and stars appeared to be fine.

The water looked very slightly hazy. I quickly checked parameters on the Profilux controller and saw pH, Conductivity (salinity inferred) and temp were all stable. I get regular emails from the controller (every 4 hours) and I had noticed earlier in the day that ORP was notably low. It usually ranges between 330 and 375mv, but was down around 250mv or so. I went back and noted that it started sometime between 4:30 PM and 8:30 PM the day prior as I saw around 335mv on the 4:30 PM email and 265mv on the 8:30 PM email. So I started thinking about what I had done that Sunday afternoon"¦

As part of my weekly maintenance routine, I spent Sunday doing a small ~10% water change with freshly mixed RO/DI and Reef Crystals brought up to the same spec gravity (checked with lab grade glass hydrometer) and temp as the display as I always do. I also changed out the two filter socks for some that I had previously washed in vinegar in the washing machine (been doing this weekly for years and I periodically replaced them with new socks from BRS).

Aside from that, I had siphoned off detritus and nuisance algae that I picked off rockwork and scraped off the back wall of the tank. I do this every week but I will note that it has been a good month or so since I scraped the back wall of the tank"¦ but not sure why it would matter. All of the siphoned off material goes direct into a filter sock in the sump which I remove and clean immediately after I'm done so it's not decomposing in the sump.

I know broken heaters can cause something freak like this to happen, but my heaters are working and there are no stray currents that I can feel. Moreover, the entire fish room is GFCI protected and the breakers never tripped.

I've thought about the possibility that my wife washed the filter socks with some detergent, but I always personally wash them myself using only vinegar and water and she confirmed that she didn't do anything but remove them from the washer and place them in the 5 gal bucket I keep them in.

I'm wondering if the Xenia decided to give off toxins for some reason. Since my discovery on Monday, I've added a couple cups of Rox to a reactor in the sump along with some fresh GFO"¦ the GFO and Rox that was in there was in there for a good month or so. I noted that the ORP started coming up immediately after changing the media so it's apparent it was removing something from the water. I also did a 10% water change. A larger water change was not possible due to not having the required volume of RO/DI water ready.

Ammonia, Nitrate and Phosphate are all safely zero or close to zero.

As of last night, the corals were looking close to normal as far as PE aside from one acro and all of the xenia. The xenia simply haven't rebounded yet so I'm starting to speculate that they may have been the source of all of this. Looking for feedback from others.

Of course, I removed all dead fish as soon as I found discovered this issue on Monday. 2 of the 3 remaining chromis passed away Monday night. The last one seems to be just fine with no signs of illness. Seriously bummed about the loss of these fish as most of them have been in the system since the early days in 2010"¦ RIP: My beloved sailfin tang, anthias, chromis and clowns.

Some specs of the system:

Born early 2010
240 gal Display in wall mounted
400-450 gal Total System
Mixed Reef, but largely SPS with some LPS (acans primarily, scoly, hammer, etc), Zoa's and Xenia
12 fish (tang, clowns, anthias and chromis)
Bare bottom (no sand bed)

All water comes from a BRS 6 Stage Chloramines RO/DI system with TDS always reading zero after the second DI canister.

Filtration:
* Bubble King 300 Deluxe External gravity fed directly by display tank overflow
* Fluidized reactor occasionally used for GAC and/or GFO
* Filter socks in sump - cleaned weekly with vinegar/water in washing machine. Socks are replaced every few months.
* Filter sponge as pre-filter to sump return pump inlet - cleaned monthly with vinegar/water
* 150 lbs+ Live Rock within system
* 40 gal Refugium (Currently without algae so lights off"¦ tough to get chaeto to stay alive with low nutrient levels)
* 35 gal Frag Tank (Currently holding live rock but no coral or lights on)
* 65 gal cryptic/live rock holding tank
* 50 gal coral growout/holding tank (currently disconnected from system and empty)
* Twin sump setup

Circulation:
* Vortech MPW40 x 2 in DT
* Tunze 6105 x 1 in DT
* Tunze Wavebox x 2 in DT (currently off line due to flaky wiring connectors)
* Jaebo RW-20 Wavemaker in DT
* Dart Gold (Sump return and feed to frag tank & fuge)

Lighting:
* 2x 250W Reeflux 12K MH's + 1x 400W Radium 20K MH "“ 7/8hr photoperiod
* 2x 80W T5's (Dimmable for sunrise/sunset) - 11 hr photoperiod
* T5's on fuge and frag tank (fuge and frag tank currently lights off)

Heating/Cooling:
* 2x 400W heater in sump and dual fans over tank controlled via Profilux.
* All tanks are housed in a dedicated fish room (In wall display).
* Fish room has its own ventilation and A/C system.
* A/C system maintains room at ~22-23C all year round
* Ventilation fan switches on every 1.5-3 hours for 30 min (depending on time of day) to exchange air with outdoors
* Tank Temperature maintained between 25.9 C (78.6 F) and 26.4 C (79.5 F) during day.
* Tank Temperature maintained between 25.4 C(77.7 F) and 25.9 C (78.6 F) during night.

Control/Supplementation/Feeding:
* Profilux II Plus EX system with ORP, pH, Temp, Salinity Control
* Profilux 4 channel dosing unit for top off (trigged by Conductivity probe) and Balling Salts (Alk, Ca and Mg)
* Roughly ½ cube frozen spirulina brine and small dime sized chunk of frozen Rod's Reef Food rinsed in tank water and then fed daily
* Was adding small quarter size piece of nori for tang per day, but not any more now
* Very small dosing of oyster feast daily via dosing pump
* Zeostart 3 slowly dosed throughout the day

Thanks in advance.

 

[tmz]

Read it . Don't have a clue. Xenia aren't particularly toxic as far as I know. If it was a decaying sacrophyton it would be a lead suspect . Sounds like something died/decayed or otherwise added extra organics to the water possibly fueling an oxygen depleting bacterial bloom.

Didn't see alk ,calcium,sg in the write up ;might be a clue there.

Were any new fish introduced recently?

 

[Oldtimer]

Thanks Tom.

No new fish... all fish have been in there for at least a year, but the majority of them for nearly 5 years and no die offs recently...one of the clowns did die unexpectedly several months ago, but I promptly removed him.

No sacrophyton or anything similar. Xenia were actually hitchhikers that I've just allowed to stay. I have maybe 2 fist fulls of it. They do not get out of control since my nutrient levels are fairly low.

Alk and Ca are stable as always...
Alk= 8.5-9.2 (Salifert)
Ca= 420-460 (Salifert)

Weekly water changes also help to buffer these and keep Mg stable, but I do dose BRS Ca/Alk... I find it uncessary to dose Mg.

Note that pH did not shift either during the event (stable around 8.5 and that's based off the Profilux electrode and a Seneye).

Oxygen depleting bacterial bloom would make some sense as one of the chromis was swimming near the top as if he was gasping for air. The source on the other hand has me baffled as there is nothing significant that I can think of which would add serve as the carbon source. I keep the tank pretty clean of detritus and the rock work is not so big such that I can move it around to siphon around and under it. Seems like there should be a more obvious answer, but I just can't put my finger on it. I want to re-stock the tank, but of course I want to know that I've resolved the issue first and not just masked it for the time being.

I had already planned on taking things out over the holidays and doing a thorough cleaning of any nuisance algae (I do get a fair bit of the lettuce algae and some byopsis) on rockwork) and just adjustment of the rocks and corals to suit my liking. So, maybe a 50% water change would be wise at the same time.

I have a 100 gal stock tank that I'll introduce new fish to before placing in the system so I would expect it to allow me time to clean out the system while the fish are acclimating.

Appreciate the pointers.

 

[Oldtimer]

sg is in the 1.023-1.026 range. It's very stable. I've checked it with the hydrometer just to have the reference, but it's controlled with my controller regulating top off water via a conductivity probe (salinity inferred from conductivity). My controller set point is 52 ms which is around 1.025-1.026 at the tank temp.

 

[ThRoewer]

Did by any chance get such things as hand lotions into the tank?
Where any chemicals, solvents or aerosols used in the house?

 

[tmz]

Sorry for your losses. Xenia tend to need higher sg; 1.023 might be a problem for them , particularly if the are from the Red Sea as most kept in the hobby are. I suppose they may have contributed somehow ;just not my first reach. Couyld be a toxin of some sort ,perhaps bad salt.

 

[Oldtimer]

Conductivity probe indicates 1.025-1.026 based on calculation from 52.0 ms. Just dropped the hydrometer in the tank now and it shows 1.024. Seems like reasonable margin of error.

Could be bad salt I suppose, but this is the same Reef Crystals that everyone else buys so seems unlikely. I get the bulk 200 gal boxes off Amazon or DrsFosterSmith.

As for the lotion... I don't use any. I'm very conscious of washing my hands and making sure they are rinsed off. That said, I have been using some oregano oil to heal something on my hand. I may have put some on that day... we're talking a couple drops, but it is a very potent antibiotic/antifungal. I had my hands in the tank for a good hour. Perhaps this could be the cause?

Just got home and Xenia look a little better today, but still far from normal. The single chromis is swimming around just fine.

 

[Oldtimer]

No aerosols in the house by the way. Also worth noting that the tank is housed within a fishroom with its own make-up air and conditioned by a mini-split A/C unit.

 

[ThRoewer]

Some substances can do a lot of harm even in trace amounts - just look at the recent findings about the harmfulness of sunscreen to the reefs and the minuscule amounts of it needed to damage/bleach corals.

 

[bertoni]

I'd be inclined to think that the oregano oil had an effect, but that's just a guess. Most likely, something toxic got into the water column. I don't think a disease could do that much damage so quickly.

 

[Oldtimer]

That's all I can come up with so note to self not to put my hands in the tank with oregano oil.... nothing else jumps out at me. Appreciate all the feedback. If something else becomes apparent, I'll report back. For now, I'll consider this a tough lesson.

 

[wpeterson]

Given you have a long-term established tank that's otherwise healthy, it sounds like hydrogen sulfide built up and released during maintenance, perhaps through disturbing an anoxic region of your sandbed or sump.

 

[Buzz1329]

Just spitballing here, but description of chromis gasping for air at surface of tank made me think of ammonia poisoning. Are gills red? I know you tested and results were good, but is it possible test kit is off/expired?

Good luck,

Mike

 

[CStrickland]

That's so sad, really sorry for your loss.
Is there any way that with the wave box offline your circulation was barely keeping up with gas exchange, and a powerhead went on the fritz pushing it over the edge? Would account for the o2 drop and gasping. Did you confirm the low o2 measure?

I recently had a powerhead start randomly running backwards sometimes and read that certain types are prone to this because they are not designed to be directional, but rather rely on a little bumper to bounce the propeller in the right direction if it starts in reverse. If the bumper falls off or the impeller gets unseated from its bushing it is more of an issue with programs that turn the pump on and off a lot of times each day because it happens randomly, so people don't always catch it in action.

Or it could've just been a random death that snowballed. Sounds like you were doing everything right

 

[tmz]

Well, I'm not feeling confident about determining causality for the troubles but here are a few thoughts:


Why a drop in ORP from 335mv to 265?

could just be noise but likely indicates an uptick in reducers like organics possibly from the oregano oil or the stressed xenia and /or other organisms. Reducers include most organics , ammonia, sulfide and many others.,so an undetected ammonia spike and/or bacterial bloom following the scraping detritus cleanup and10% water change is a possibility

This article on ORP may be of interest since you are monitoring it:

http://reefkeeping.com/issues/2003-12/rhf/feature/index.htm

Why hazy water and fish deaths?

Ammonia could do it. Exudates from the xenia might contriute organics or they may come from other sources like decaying dead organisms contriguting to a bacterial bloom The oregano could play role; though I haven't found anything tying it to lethality in aquatic animals like there is for pyrethroids from crysanthemums as an example of harmful plant by products.

The xenia are thought to take up orgnaics from the water directly ,more so than other corals, so maybe that's why they are singularly most affected .

I doubt the socks have accumulated enough organic carbon from the vinegar to be an issue.

The Rox should help a lot. Might try some polypad or cuprisorb in case some other toxin like a free heavy metal got in there.

 

[Oldtimer]

Thanks again for all the feedback everyone.

As for hydrogen sulfide... while I wouldn't rule it out entirely, I don't have a sandbed and I didn't stir anything more than I would normally do on a weekly basis while cleaning. By stirring, I'm referring to siphoning off detritus into a filter sock which I promptly when I'm finished. I can't think of anything I might have disturbed that would have harbored a build up of hydrogen sulfide. By that, I mean I was tending to areas that I normally clean and they don't require any significant movement of rockwork, etc... my rockscape is fairly well open and I can navigate pretty well around the coral.

As for water circulation, currently operating in the DT are (2) Vortech MPW40's, (1) Tunze 6105 and (1) Jaebo RW-20 Wavemaker. In addition, the Dart Gold is handling return water from the sumps. There is plenty of random flow in the DT and from multiple sources so I don't think flow is an issue.

No red gills on the fish to indicate ammonia poisoning.

Thanks for the link to the RHF ORP article. I recall reading that one in the past, but worth a refresh.

Xenia are definitely recovering showing signs of improvements every day.

Bought some new fish to take my mind off this. They are doing well in QT.

I'll throw a polypad in there to be safe. ROX is definitely helping. FWIW - my skimmer never went nuts during the event.

 

[tmz]

Sounds like a rebound is under way. Good luck ; enjoy the new fish.

 

[Sk8r]

Once a species dieoff happens if abundant, it could trigger a cascade of species dieoffs worsening the water at every stage. Don't know if it could have been the xenia, but...??

I just got of a weeklong power out, and in the cold and the lack of circulation I lost fish and inverts pretty well by species, one after another (got 4 fish, a few crabs, and certain snails through alive) as they hit their limits. At high temperatures, (mine hovered around 66 degrees) a cascade could go within hours. No comfort, I know, and there's still the question what touched off the chain.

 

[Oldtimer]

I've also noted that my acros have lost their color. Everything has been rebounding, but I think the acro color loss may have been more gradual as compared to the fish loss. EVerything has normal PE now so I really think whatever was in the water is no longer.

 

[bertoni]

Well, hopefully, the tank will recover completely in a few weeks. I am not sure what happened.