Multiple mysterious deaths overnight, help needed with causes

[TheWB]

Hello all,

A friend of mine has lost many of the fish in one of his tanks last night with no discernible reason as to what happened. He is looking for some possibilities as to the cause. Here is what I know so far.
He lost a Clown Tang, a Powder Blue Tang, a jawfish, a Copper banded butterfly, a fairy wrasse, 4 mandarins, a hawk fish, a cardinal and a peppermint shrimp. None showed any signs of illness. No spots or blemishes.
Two Clowns have been moved to another tank where they look sluggish.
A Blue Tang and a Foxface are still in the tank and showing no signs of stress at all along with a cleaner shrimp.
No corals show any sign of problems. It’s a mixed reef including some nps and a Colorado BTA.
This morning when he discovered the deaths Alk was 9, ph was 8.1, orp was 439 and temp was 77. Those are pretty stable numbers for this tank. An ICP test is being sent out.

He’s never experienced a loss of this magnitude with no explanation and is looking for possibilities to explore. I realize that there isn’t a lot ofinformation here to go on but if anyone has experienced something like this before where overnight everything went from being fine to massive fish loss in the morning, or has a suggestion on what might be a possible cause please feel free to jump in. Any thoughts or ideas are appreciated.

Here is a FTS from today after the dead fish were removed.

 

[Tired]

Looks like a pretty full tank. Any chance there was an equipment malfunction, maybe a stopped pump, that cut the oxygen for awhile?

Any coral stress or coral deaths?

 

[TheWB]

Looks like a pretty full tank. Any chance there was an equipment malfunction, maybe a stopped pump, that cut the oxygen for awhile?

Any coral stress or coral deaths?

Nope, coral is all fine and no equipment failure that was obvious as far as I know.

 

[vetteguy53081]

Hello all,

A friend of mine has lost many of the fish in one of his tanks last night with no discernible reason as to what happened. He is looking for some possibilities as to the cause. Here is what I know so far.
He lost a Clown Tang, a Powder Blue Tang, a jawfish, a Copper banded butterfly, a fairy wrasse, 4 mandarins, a hawk fish, a cardinal and a peppermint shrimp. None showed any signs of illness. No spots or blemishes.
Two Clowns have been moved to another tank where they look sluggish.
A Blue Tang and a Foxface are still in the tank and showing no signs of stress at all along with a cleaner shrimp.
No corals show any sign of problems. It’s a mixed reef including some nps and a Colorado BTA.
This morning when he discovered the deaths Alk was 9, ph was 8.1, orp was 439 and temp was 77. Those are pretty stable numbers for this tank. An ICP test is being sent out.

He’s never experienced a loss of this magnitude with no explanation and is looking for possibilities to explore. I realize that there isn’t a lot ofinformation here to go on but if anyone has experienced something like this before where overnight everything went from being fine to massive fish loss in the morning, or has a suggestion on what might be a possible cause please feel free to jump in. Any thoughts or ideas are appreciated.

Here is a FTS from today after the dead fish were removed.

Rabbit looks somewhat thin. Any changes in water or foods?
I see a red linkia start on glass which is sensitive to water quality so dont believe its chemistry.
Any stray voltage or zap if finger is placed in tank ?
Any recent use of chemicals or aerosols near tank ?

 

[MichaelReefer]

Stray voltage?

 

[TheWB]

Rabbit looks somewhat thin. Any changes in water or foods?
I see a red linkia start on glass which is sensitive to water quality so dnt believe its schemistry.
Any stray voltage or zap if finger is placed in tank ?
Any recent use of chemicals or aerosols near tank ?

Thanks for responding. No to chemical/aerosol usage around the tank or changes to water or food. No stray voltage, is there any way to test fo that? All electrical cords have been inspected. No new additions to the tank for months either.

 

[Sharkbait19]

Are there any pics or videos of the fish before they died? Are the living fish acting/looking off at all?

 

[TheWB]

Are there any pics or videos of the fish before they died? Are the living fish acting/looking off at all?

No recent video.
The survivors all look just fine. No signs of any problems.
I just got an update on the timeline though. I misunderstood. All fish were alive at feeding time this morning at 10am. They died sometime between then and when I received the text before I posted this thread. They were fed mysis which they get regularly.

 

[vetteguy53081]

No recent video.
The survivors all look just fine. No signs of any problems.
I just got an update on the timeline though. I misunderstood. All fish were alive at feeding time this morning at 10am. They died sometime between then and when I received the text before I posted this thread. They were fed mysis which they get regularly.

A nitrate or ammonia spike would do this as would electric shock - With stray voltage- either a voltage meter reading or sticking finger in water you would feel a sting.
Any pets in the house that could have urinated in the sump (yes it does happen)?

@Jay Hemdal

 

[TheWB]

A nitrate or ammonia spike would do this as would electric shock - With stray voltage- either a voltage meter reading or sticking finger in water you would feel a sting.
Any pets in the house that could have urinated in the sump (yes it does happen)?

@Jay Hemdal

There’s no noticeable sting or anything from putting hands in the water.
No pets had access to the sump.
Could‘ve been a spike of something but no abnormal test readings. He didn’t have an ammonia test, it had expired a while ago. I would think that starfish would have perished if there was enough ammonia to kill the fish though.

 

[killer2001]

Ammonia Spike -> Bacterial Bloom -> Oxygen Deprivation... only thing that makes sense in my mind other then actual toxic substance being dumped into the tank.

 

[V A R I A N T]

Looking at the corals, the softies have low polyp extension, the sps appears pale, and some of the lps has limited polyp extension. The food or liquids mixed with the food could be the issue, but my mind goes to contaminates being introduced through the ATO. Could the top off water, or RODI be the issue? Any possibility of airborne contamination? I recently watched a video where the tank owner had their windows open and pesticide was sprayed outdoors that made it into the tank and killed the livestock. Whatever the cause, it seems like a contaminate and something that may have filtered out within hours.

 

[TheWB]

Ammonia Spike -> Bacterial Bloom -> Oxygen Deprivation... only thing that makes sense in my mind other then actual toxic substance being dumped into the tank.

Thanks, that very well could be what happened.

 

[skyjacker07]

Have your friend check for sure, I had a fish mysteriously die recently. Couldn’t figure it out, I had a massive ammonia spike for some reason and it ended up taking 5 fish, it took a bit to get it under control but the tank is back to happy again.

 

[TheWB]

Looking at the corals, the softies have low polyp extension, the sps appears pale, and some of the lps has limited polyp extension. The food or liquids mixed with the food could be the issue, but my mind goes to contaminates being introduced through the ATO. Could the top off water, or RODI be the issue? Any possibility of airborne contamination? I recently watched a video where the tank owner had their windows open and pesticide was sprayed outdoors that made it into the tank and killed the livestock. Whatever the cause, it seems like a contaminate and something that may have filtered out within hours.

I think the colors are just washed out in that particular picture as far as pale colors go. The tank owner is a pretty experienced reefer and that tank has been thriving for about two years.
It very well could have been the food. Based on the timeline I think that makes the most sense but hard to know for sure.

 

[TheWB]

Have your friend check for sure, I had a fish mysteriously die recently. Couldn’t figure it out, I had a massive ammonia spike for some reason and it ended up taking 5 fish, it took a bit to get it under control but the tank is back to happy again.

He’s going to. It’s also a reminder for me to make sure I have an ammonia badge on hand, don’t think I do.

 

[V A R I A N T]

I think the colors are just washed out in that particular picture as far as pale colors go. The tank owner is a pretty experienced reefer and that tank has been thriving for about two years.
It very well could have been the food. Based on the timeline I think that makes the most sense but hard to know for sure.

Make up another batch of food and smell it. Sometimes the nose knows!

 

[Jay Hemdal]

This is a tough one. I agree that the foxface is skinny, but then, it survived, right?

I can tell you what didn't happen - it isn't ammonia or stray voltage. Disease issues often kill fish but leave invertebrates alone, but the timing is too fast (unless the owner missed early signs of rapid breathing in the fish). It is unlikely to be a toxin in the water, again because the corals are o.k., but also because some fish survived.

So that leaves transient low dissolved oxygen or high carbon dioxide. If there was a power failure, or even some temporary reduction in aeration (the tank is pretty crowded) the fish would die quickly, but the corals would often be fine. Some fish have different oxygen requirements, so that accounts for some still alive.

I cannot speculate on the rancid food idea. I've never seen that happen, but it could be possible?

Jay

 

[TheWB]

This is a tough one. I agree that the foxface is skinny, but then, it survived, right?

I can tell you what didn't happen - it isn't ammonia or stray voltage. Disease issues often kill fish but leave invertebrates alone, but the timing is too fast (unless the owner missed early signs of rapid breathing in the fish). It is unlikely to be a toxin in the water, again because the corals are o.k., but also because some fish survived.

So that leaves transient low dissolved oxygen or high carbon dioxide. If there was a power failure, or even some temporary reduction in aeration (the tank is pretty crowded) the fish would die quickly, but the corals would often be fine. Some fish have different oxygen requirements, so that accounts for some still alive.

I cannot speculate on the rancid food idea. I've never seen that happen, but it could be possible?

Jay

Thanks Jay. The rest of the fish died over a 3 hour period last night after I started this thread. That tank was pretty crowded but it had been that way for 2 years. The fish were acting normally at their 10am feeding and in less than 12 hours they all are dead with no obvious external signs of what the cause is. You are probably right about it being a dissolved oxygen issue but there was no power outage or loss of aeration in the tank. An icp test of the tank water is being sent out so that may yield some answers but we may never know what actually happened. Such a shame, those fish were beautiful and seemingly in great health, they were all very fat the last time I saw them.

Thanks to everyone who replied and tried to help. Since all the fish died there will be a complete tear down of the tank and sump for cleaning and reboot.

 

[OrionN]

I agree with Jay. IMO most likely cause was transient decrease in O2. Fish in case like list will act completely normal after the light turn on again. Often you will see worms crawling out of the rock work and sand looking for higher O2. They too will completely recover once the light turn on again. If the hypoxemia is worst to the point of some of the invertebrates (fauna also died) the. Your tank will crash as this will release ammonia and crash your reef.

do you have overflow? Skimmer?
Do you turn off your skimmer at night?

Other toxin will cause death of invertebrates and corals also, so unlikely to be the cause in this case.