All my fish died after water change

Ladie2K19 · Jun 20, 2019

Hey all,

New member here and could use some advice. Last night I did a usual 10% water change in my 65 gal fish and invert tank. My fish were 2 Percula Clowns, Tomini Tang, Royal Gramma and Six Line Wrasse. I also have some Trocus Snails, Hermits, a Camelback Shrimp, and a Curly Cue Pistol Shrimp.

The tank is about 3 months old and all my parameters ( Ammonia, Nitrite, Nitrate) all perfect. I use Purigen and ChemiPure Elite as my chem filtration and I have a skimmer running as well as using a liter of Pond Matrix for Biofiltration. Salinity was at 34 with my refractometer and PH was about 8 (hard to differentiate some colors with the API test kits) and Alk was about 9.

Anyway, I did my normal things during the WC, vacuum the sand bed for diatoms (still in this phase) and the live rock. Then to add water I keep RO/DI water in a 35 gal trash can in my basement. The water in there is probably kept for about 2 weeks before I add more. I just switched my salt from Red Sea to Red Sea Coral Pro. Mixed the saltwater as usual and let sit for a bit then added two 5 gal buckets worth to my tank. Again nothing out of the ordinary.

About two hours later the lights went off for the evening and everything was fine. Another hour before I went to bed I checked on the tank and all my fish, except for the wrasse, were either dead or dying. I immediately checked my parameters with my Ammonia looking like between o and .25 (again kind of hard to tell with the color) Nitrite at 0 and PH looking like around 8. This morning I woke up and the wrasse was still alive but hiding and all of my inverts were fine too. I don't have much faith the wrasse will last much longer and I honestly have no idea what could have happened.

Could the salt change have done something? Stray voltage? Could that bit of ammonia if there was any do that? Just weird it happen right after a WC. Now I'm freaked out to add anything to the tank without basically tearing it all down. Any suggestions would be great. Thanks everyone.

acro-ed · Jun 20, 2019

It is possible that your tank was already borderline on having sufficient ammonia-oxydizing/nitrifying bacteria and the water change and sand vacuum was enough to cause the deficiency which led to the detectable ammonia. Ammonia can definitely kill fish. Can you include a pic of the tank? Sorry for your situation and hopefully things perk up soon!

Ladie2K19 · Jun 20, 2019

Here is a pic of my tank...Also I forgot to mention as soon as I saw that there was a potential for Ammonia I added Seachem Prime that I keep on hand just in case. During my cycle phase I probably added 2 bottles of Dr. Tims and 3 bottles of Seachem Stability

jrill · Jun 20, 2019

Pro has a higher ALK. Did you check that on the pH change.

Ladie2K19 · Jun 20, 2019

I tested the pH last night and this morning which both times looked to be around 8. When I did the WC, the amount of Pro I used was maybe a cup or so because I ran out of the regular during the change.

12gallonsofhex · Jun 20, 2019

Thats a bummer. Sorry you lost your fish. Just wanted to say that if you are using an API test kit they have been known to show a false reading of ammonia. You might want to pick up a different ammonia test kit to eliminate that as a possibility.

brandon429 · Jun 20, 2019

The use of Prime makes all future ammonia testing wrong until your water is fully changed. You’ve arrested any ammonia issues with its use so that’s ok. Do you store your water change water in sealed buckets, or are they vented such that you have to top off your change water as it sits?

Wanting to know if you store your ro water, or pre made change water, sealed. They need to breathe/ sealed storage containers can go anoxic when a few conditions are present in the water holding vessel/ all 02 cut off it almost killed my tank once, I could smell the rot in the makeup water container

You only changed ten pct which is very low, so if it’s some other contaminant that would not surprise, at 10% something was really lethal here and rare.

BestMomEver · Jun 20, 2019

That’s really sad. I’m so sorry. The first thing that came to mind was chlorine but then I read you have RO water. Do the cartridges need changing? I use the Pro salt and never had issues but I mix it as I need it. I don’t store it. Is it possible you had a sick fish and didn’t know it? Maybe the stress of a water change caused an issue. I also might mix up a new small batch of water and test it.

BestMomEver · Jun 20, 2019

Where are my manners? Welcome to the reef! We’ll get this sorted out.

Ladie2K19 · Jun 20, 2019

brandon429 said:
The use of Prime makes all future ammonia testing wrong until your water is fully changed. You’ve arrested any ammonia issues with its use so that’s ok. Do you store your water change water in sealed buckets, or are they vented such that you have to top off your change water as it sits?

Wanting to know if you store your ro water, or pre made change water, sealed. They need to breathe/ sealed storage containers can go anoxic when a few conditions are present in the water holding vessel/ all 02 cut off it almost killed my tank once, I could smell the rot in the makeup water container

You only changed ten pct which is very low, so if it’s some other contaminant that would not surprise, at 10% something was really lethal here and rare.

Yes, I definitely know Prime will shoot ammonia tests to 0, I was just hoping if that was the cause at the moment I could protect the fish until I could figure out a solution and getting a 0 reading was what I was hoping for.

I agree on the sealing and that was something I thought of, but in the can I keep my water in I have the lid slightly askew so air can get in. I am worried that maybe something somehow got in the open part and into the water.

If it was some sort of chemical that got in that I'm unaware of I'm now worried about ever adding anymore fish unless I totally clean out all the water. Does ATI mail in testing show chemicals like that? I'm also worried that if it is something, it leeched into the sand of the rock. I just think it's strange the inverts are all ok, when I would have thought they would be even moer sensitive than fish to any sort of chemicals.

BestMomEver · Jun 20, 2019

Send in an ICP test before you tear your tank apart. It only takes a week or so. That will tell you the exact problem if it’s chemical. If it was a hiding pathogen you may never know.

brandon429 · Jun 20, 2019

I’m stumped so far

For sure in our sand rinse thread we collected examples of detritus from sandbeds being upwelled and killing things but your tank is pretty new and a 10% change doesn’t kick up a bunch of waste even if you had an old sandbed. Nice call on fast pathogen that’s really good catch, how was quarantine / fallow ran here in prep

ajhudson15 · Jun 20, 2019

switching salts and changing that little amount of water should have caused enough spike to hurt anything. any chance you clean your equipment in bleach and didn't rinse off good enough before use? any chance your basement is unfinished and theres mold or anything that could have made its way into the water?

Joel B. · Jun 20, 2019

Anytime something happens that quickly and shortly after a water change I assume some kind of contamination got into the holding water, and that's what I would investigate first. Any chance for something like bleach, copper, pesticides, etc.

Ladie2K19 · Jun 20, 2019

ajhudson15 said:
switching salts and changing that little amount of water should have caused enough spike to hurt anything. any chance you clean your equipment in bleach and didn't rinse off good enough before use? any chance your basement is unfinished and theres mold or anything that could have made its way into the water?

Absolutely keep all harsh chemicals away from anything that goes into the tank. If I rinse any equipment it's with whatever left over RODI water I have in my top off container or, if I'm brushing diatoms off my rock it's in the saltwater I pulled out of the tank with maybe only one or two small rocks at a time.

I'm completely at a loss. My quarantine was fine, nothing out of the ordinary and all the fish ate like crazy before I did the water change.

Brew12 · Jun 20, 2019

I'm sorry you are going through this.

How is it you are measuring salinity? Is it possible that the salt water you added was a much stronger concentration than what was in your tank originally?

As an FYI, Prime should not interfere with your ammonia test kit. The binding action reduces the toxicity but it shouldn't impact test kit readings or the ability for it to be processed by nitrifying bacteria.

Ladie2K19 · Jun 20, 2019

Joel B. said:
Anytime something happens that quickly and shortly after a water change I assume some kind of contamination got into the holding water, and that's what I would investigate first. Any chance for something like bleach, copper, pesticides, etc.

That's pretty much what I'm suspecting. I don't know how it would have happened, but maybe something leaked down from the basement ceiling and got into my water can. We have had tons of rain lately and everything is flooding.

If that would be the case I just don't understand how the inverts are still alive and, when I would decide to add fish again, how to know if it's safe.

Xam · Jun 20, 2019

Ladie2K19 said:
I agree on the sealing and that was something I thought of, but in the can I keep my water in I have the lid slightly askew so air can get in. I am worried that maybe something somehow got in the open part and into the water.

BestMomEver said:
Send in an ICP test before you tear your tank apart. It only takes a week or so. That will tell you the exact problem if it’s chemical. If it was a hiding pathogen you may never know.

++ on these two pieces of info - maybe insecticide got in the container? Just as BestMomEver suggested, a high-grade water analysis would most likely tell what happened here.