Fish suddenly dying but parameters seem fine

[Algae_Farmer]

Any suggestions on what to check? (I already asked the kids if they threw anything random in, so far no admissions).
Thanks in advance!

Suddenly fish have started dying, only difference is new frozen food I bought in a pinch at petco (SF Bay Brand mysis and "Emerald Entree" - never used that before)
In the last week I lost:
Matted filefish
Firefish
Purple firefish
Bangaii cardinal
Bicolor dottyback
Gold head sleeper goby
(maybe candy cane shrimp, haven't seen it)

Still alive today, and eating fine (I stopped giving them the new mysis and Emerald Entree after noticing the deaths and just switched to frozen brine shrimp):
Bangaii cardinal
2 percula clowns
Gold midas blenny
Red pincushion urchin
(asterina stars seem to be doing fine :/ )

I've also got several soft coral, LPS, zoas, rhodactis, and green polyps - all are doing great. Except for a wierd white sponge glob that came with some live rock, it looks like it's maybe dying.
I had some GHA but it started disappearing on its own recently, also minor cyano on the bottom but stable and not bad.

Aquarium Parameters:
PH: 8.15
Temp: 78
NO3: 5ppm
PO4: 0.1 ppm
NH3: 0
KH: 10 dKH
Ca: 380 ppm
I did just get a new refractometer and realized SG was 1.028 or 9. I usually try for 1.025 so I'm slowly adding DI.
I had been using RO water only with about 10 PPM TDS but switched to RODI a few months ago, so a couple water changes and all top off is now 0 PPM TDS.

Aquarium setup:
System has been running well for 18 Mos. 90 gal DT with 60 gal sump/fuge in the basement (90 gal tank with homemade baffles). Filtration is reef octo skimmer, filter sock on sump inlet, and occasional use of Marineland Magnum hang-on-tank 250 micron filter. Also the sump has granular carbon pillows and a Jaubert type DSB/plenum and chaeto.

Lighting is 4 T5HO (ATI coral plus blue plus and actinic) in the DT, 2 bulbs at 12 hrs and 2 more at 5 hrs. Cheap LED grow bulb in the sump 24/7 (seems to work fine for chaeto)

 

[Rickybobby]

What have you added to the tank lately livestock wise??

 

[Algae_Farmer]

Here are pics of DT and Sump

 

[Algae_Farmer]

What have you added to the tank lately livestock wise??

Most recent were the 2 Bangaii, about 3 months ago. Honestly not much has changed in months except the food, and switching to RODI. I haven't done a water change in about 5 weeks because I was waiting for salt. (what's up with the salt shortage?)

 

[dvgyfresh]

Any damage on the dead fish? Just listing possibilities , maybe stray voltage , contaminated from outside source like cleaning product.

 

[Algae_Farmer]

Any damage on the dead fish? Just listing possibilities , maybe stray voltage , contaminated from outside source like cleaning product.

Good questions.
No noticeable damage on fish (except decay), no fungus, holes or strange marks/spots.
I have a ground rod going to electrical ground.

Household chemicals are a possibility as DT is open top, also possible kid did toss something in, although I haven't found anything odd in there lately...

 

[dvgyfresh]

Good questions.
No noticeable damage on fish (except decay), no fungus, holes or strange marks/spots.
I have a ground rod going to electrical ground.

Household chemicals are a possibility as DT is open top, also possible kid did toss something in, although I haven't found anything odd in there lately...

That is odd, something happend to contribute to the death of all, I’m leaning towards a contaminate or something getting into water because everything else seems fine , maybe send an ICP test and then put some cuprisorb or something in the sump just in case

 

[Algae_Farmer]

That is odd, something happend to contribute to the death of all, I’m leaning towards a contaminate or something getting into water because everything else seems fine , maybe send an ICP test and then put some cuprisorb or something in the sump just in case

Thanks! Good ideas, will try...

 

[Garf]

Is that a temperature probe floating around at the top of the display?

 

[Algae_Farmer]

Is that a temperature probe floating around at the top of the display?

Yes, suction cup keeps coming off the back. It's zip tied to the top center brace so it stays down in place though.

 

[Garf]

Yes, suction cup keeps coming off the back. It's zip tied to the top center brace so it stays down in place though.

Does your Chaeto grow?

 

[Algae_Farmer]

Yeah, it's added maybe 20% volume in ~4 months? My N&P are usually pretty low though, been considering dosing them. The 5 & 0.1 above are higher than it usually is.

 

[Jedi1199]

I haven't found anything odd in there lately...

That cracked me up "Lately".. haha ;Playful Just how many times HAVE you found odd things in the tank?

 

[resortez]

The times I’ve seen these types of sudden deaths in short periods, it’s been some foreign substance enters the system & swings parameters out of control, especially the PH & ammonia or nitrites flash on the test. In one case it was the RO source, a chemical was sprayed near the RO system without the owner knowing, that contaminated the supply & eventually made its way to the display through water change & top off. Also seen this when a large amount of water is changed or a large amount of beneficial bacteria is removed through switching sand, removing/replacing rocks, reactors are removed/cleaned, making the tank go anaerobic. Stray voltage from a powerhead, heater, pump, etc. but you mentioned the tank is grounded. Power outages causing O2 & temps to drop & fluctuating parameters. Lastly, an internal parasitic disease. Those internal infections are the worst because there is no way of seeing if a fish is a carrier, why QT is highly recommended. I can’t stress enough how important it is to QT every new fish you introduce to your main display. The heartache is more costly than putting together a $100 QT system.

 

[LegendaryCG]

Not sure what’s going on on your tank but just wanted to say I’ve fed SF bay mysis and emerald entree many, many times to my tanks without a noticeable issue.

 

[Garf]

The corals don’t seem good and it doesn’t look like an 18month tank to me. I know what I would do. I would move the tank to where it is now. Mix up some new salt using a properly calibrated refractometer (to 35ppt) and heated, take out all the rocks, fish and coral, rinse the sand with tap, get the temperature control sorted, get the rubbish out of the rocks by rinsing in the old tank water, raise the return line (or make sure there’s a syphon break), remove that hang on thing, sort the pump wiring and clean the display tank. Then refill with your clean sand and new water and replace everything. Voila, new safe system you can cherish. Treat yourself to some corals then after a few months if you don’t get any more death, fish. The best cure for L.A.R.S.

 

[Patryk1982]

Hello. make and send ICP tests. Has anyone near the aquarium or sump used perfume or deodorant? . look carefully at the aquarium and the sump, maybe some piece of metal is lying there

 

[gentlefish]

So corals are fine, fish are not.... how about the snails? If they were fine, I do believe in fish disease over contamination. Did you fresh water dip one of the fish or fatalities for flukes?

 

[Algae_Farmer]

Not sure what’s going on on your tank but just wanted to say I’ve fed SF bay mysis and emerald entree many, many times to my tanks without a noticeable issue.

Thanks for mentioning this. Helps rule out the paranoia of a new (to me) product.

 

[Algae_Farmer]

So corals are fine, fish are not.... how about the snails? If they were fine, I do believe in fish disease over contamination. Did you fresh water dip one of the fish or fatalities for flukes?

Correct re fish n corals, snails are OK, just noticed WAY more than usual of my Nassarius Vibex are on the glass instead of in the gravel?

Freshwater dip? No, what's that?