Mass Casualty In My Tank This Morning

[Pet Detective]

This morning I woke up to find a mass casualty if fish in my tank.

65 gal
Bare Bottom
Marine Land External Canister Filter
Water was tested prior to relocating the canister last night, all was good.

Fish:
Six Discus (4 approximately 4 1/2"-5", 2 approximately 3 1'/2"
5 tetras
3 Siamese Algae eaters (3")
1 Placo approx 2 1/2"

I believe something toxic got in the water that killed everyone. The placo for some reason survived and is still swimming around.


Timeline:
1. Needed to move the canister to a new location. The distance was 7' from the tank, which required me to purchase new tubing. I found DAVCO 3/4" ID × 1" OD - 25 ft Clear Braided Plastic Vinyl Tubing Flexible High Pressure Reinforced PVC Hose Brand: DAVCO on Amazon.
2. We moved the canister last night (9:00pm)and connected the tubing.
3. Completed a 50% water change and vacuum using water from my holding tank
4. While this was under way, I added an artificial piece of driftwood and a sandstone rock that was in a box from a tank I had six months ago. Both pieces were clean and did not appear to have any obvious signs of any contamination, or I wouldn't have placed it in the tank.

The fish were not showing any signs of distress prior to this happening. All appeared to be healthy, but at 8:30 this morning I woke up to find everyone dead (except for the placo).

I am suspicious that something toxic got into the tank either from the tubing or my holding tank. Does anyone have any experience with anything like this?

[samurai.cichlid]

Jeez, sorry to hear about the loss.

To me at least, nothing jumps out as the obvious culprit. It could be any one thing (or any combination of things) and it would all be based on excessive speculation.

Obviously I don't want to suggest something I don't know for sure, but I feel like when I've bought things off Amazon in the past I've had items that were returned sent back out to me as "new". So, it could well be the new tubing you had had maybe been used for something else? Then returned and unscrupulously sent back out to you as a new product by a shady third party seller. Unlikely, I know. But, maybe it's possible?

The sandstone could be the culprit too, being pourous maybe it picked something up and then seeped it back into the water? Again, unlikely if it had been stored safely and used in a tank previously without issue.

Maybe in the move you lost your cycle on your filter media? Another unlikely one though, because it'd have to be dry for a while for all the bacteria to die.

Could also be oxygen depletion. I know in low o2 situations plecos will gulp air from the surface to get by. Your oxygen could be low for a few reasons. If you do a large water change and your tap water contains chloramines, then the dechlorinator requisitions oxygen from the water as part of the chemical reaction that does away with said chloramines (an actual chemist could explain it better than me haha). Also, maybe you had a heater malfunction, which would also cause a big die off due to low oxygen. Although, you'd likely notice the water extremely warm to the touch for that to have been the problem.

When it comes to toxins in the tank, the question a lot of the time is not if a particular substance is toxic, but rather in what concentration is it toxic. I'm not sure of something commonly found in houses that could accidently end up in the tank, in enough volume, that could kill everything but the pleco like that. I've had people spray nasty smelling air fresheners right next to the aquarium and worried for days, but noticed no ill effects.

Without more info, the kind of info that's difficult to ascertain honestly, you might never know what caused the deaths unfortunately. It goes without saying but if you suspect some sort of contamination, I'd break the tank down, scrub it with a blue dawn solution, hose it out and start over.

Maybe somebody else on the forum has some better insight than my few speculations there, but it's all I could think of.

[Second Hand Pat]

Hi Bernie, did the canister sit idle for a while with no water running thru it and closed? I have read of people leaving canisters closed and not running for as little as two hours and the closed system kills the BB which can be toxic when turned on.
Pat

[Iminit]

I’m with D’bunk 7’ is way to far for a canister to pump water. 4’ would be topping out on most. It may have showed flow but it had to be drastically reduced. Now that in it self shouldn’t have been that lethal. So unless there was a problem with the new water (you used prime?) Next would be the decorations. Sorry for the loss.

[Pet Detective]

Thank you all for input on this. Since nobody commented on the new tubing being the possible culprit, low oxygen and standing water in the canister may have been a contributor. However, before we moved the canister, we emptied about 3 gallons of water out of it so that we could lift it. The lid was not removed so the water was contained inside for probably two to three hours before we got the hoses reconnected. The media inside the filter was established since it was transferred from old canister three weeks ago. During the water change and filter transition, I removed the UV filter to clean it, so I was only relying on the canister filter to do the job. I also removed the air bubbler because the new Marineland C-530 had so much power, however, I did not create a spray bar. Since the water in the holding tank had been aged for 9 days, does it seem likely that Samurai-Cichlid could be right?

[bluelagoon]

Just guessing here. Does your water source use chlorine or chloramine? If chloramine, when do you or how do you use the Prime. For example, you would not want to let the conditioner Prime to be in your aging barrel for more than 24 hours before use. It will break the bond and ammonia will be in you aged water.

[CliffsDiscus]

Hi Bernie, did the canister sit idle for a while with no water running thru it and closed? I have read of people leaving canisters closed and not running for as little as two hours and the closed system kills the BB which can be toxic when turned on.
Pat

This happens really fairly often, someone unplugging the electrical plug to charge their phone or laptop and forgetting to replug the filter.
Then there is the lower flow thru the filter because of the longer tubing.

Cliff

[fljones3]

Another guess but combining the too long distance from the tank + much lower flow. As it killed off the bacteria then it could have become toxic.
Sorry for the devastation.

[Pet Detective]

I understand the distance from the tank being a concern, but the old canister I had, pennplax cascade, was only doing half the job, so I replaced it with the marineland. The tank is 65 gallons, so even though the distance is somewhere between 6.5 and 7 feet, I am not sure the flow rate was so low that it would have caused sudden death. I am really perplexed by this, because the only variable that played a key role was the tubing. If the bacteria will die off in just a couple of hours while we had to turn the system off to move it and reattach everything, that is pretty shocking. There was probably a gallon or two in the canister when we moved it, the cover was not removed. I did not add prime to the holding tank when I filled it 10 days ago, I keep an air bubbler and heater in it so it would be ready to use. When the water in the holding tank was nearing the bottom, I added prime when I added more water to it. So, the water used near the end of the water change was a modest mixture of tap water mixed with the aged water and little bit of prime added. Probably 3-5 gallons.

[fljones3]

I just saw that you are in Richmond. I live in Chesterfield. Their water changes in the late fall which can affect the fish. I lost 6 of 8 discus after a water change a couple of years ago even though the water dept said nothing changed. This is just another guess.

[Jack L]

"While this was under way, I added an artificial piece of driftwood and a sandstone rock that was in a box from a tank I had six months ago. "
where these used before by you in a tank without issue? assuming yes.

you age your water, i assume you use prime or safe too.

my hunch would be that tubing. something maybe on it from the manufacturing process. but that is a guess.

[CJC]

Stray voltage? Electrification of the water from something unshielded? Heaters are the most common culprit. So sorry!

[Disgirl]

The only time(s) I have ever had such a thing happen is when I forgot to add Prime/Safe. Chlorine and Chloramine kill fast.
Barb

[Pet Detective]

Second Hand Pat I think you may be right (I have read of people leaving canisters closed and not running for as little as two hours and the closed system kills the BB which can be toxic when turned on) and D'Bunk you too! (the ammonia spike as well, but it takes bacteria longer to process nitrite than ammonia, so it's more likely that nitrite would be the problem.)
The day after Thanksgiving we left for a weeklong vacation in the Virgin Islands. I left the tank running as if fish were in it. When we returned Sunday, the aquarium was completely covered with an algae bloom as if the tank was cycling for the first time. Prior to relocating the new canister and doing the water change, the water was clean and fish were healthy. Do you think if the bacteria died during the two-three hour period while we moved the canister and set everything up, coupled with the low oxygen due to the aged water in the holding tank plus low-zero aeration would have caused a massive rise in nitrite which turned toxic? Please respond if this would all make sense, or not. I really need to know so that I don't do something like this again.

[Second Hand Pat]

Not sure Bernie, best to test when in doubt. You can add salt to assist the fish when nitrites are present. The salt prevents the fish from taking the nitrate internally. Look up brown blood disease.
Pat

[Iminit]

I don’t know about the die off in the canister. I shut mine off for every water change and have forgotten many times to turn it back on. As long as 12hr and never had a problem when turning it back on. Bacteria takes time to start dying off. I even left it for 2+ days once and only realized when the water started getting cloudy. That time I cleaned the filter before turning it back on. When turned back on all was fine. I’m with the distance was just too far and the flow drastically decreased. Or something in the new water going in.

[Pet Detective]

Hi Bernie, did the canister sit idle for a while with no water running thru it and closed? I have read of people leaving canisters closed and not running for as little as two hours and the closed system kills the BB which can be toxic when turned on.
Pat

Just days after the catastrophe in my tank we left for a trip and didn't return until December 5th. Upon our return, my empty tank that only had the pleco in it,had an enormous algae bloom. This was a clear sign that the tank was lacking bacteria and needed to recycle. This supports your suggestion that during the switch over, which took two-three hours, the bacteria died. The low oxygen in the water from the aging tank only added to the problem since I removed the air bubbler and had no spray bar. The idea that a toxic reaction occurred in the canister from the depleted and stagnant water all makes sense. After I added bacteria to the tank, and some fish, everything cleared up and the tetras have been doing fine for about 4 weeks now. I am in the process of cycling a quarantine tank for new discus arrivals, hopefully in a few weeks. So, I am thankful for your input, it helped me eliminate all the other thoughts, especially when I came home from our trip to see the tank experiencing the algae bloom. I never thought for one minute that the bacteria would die in my canister and then cause so many problems. Thank you for helping me figure this out. I will post a new thread when I get the quarantine tank cycled and expect the newbies.

[jpm995]

As others have noted 7' is a long run. The filter should have specs on pump head volume at different heights. Did you feel the output flow to the tank? Can you tell the difference from before? You could hold a bucket where the water returns to the tank, time how long it takes to fill one gallon and get an estimate of the gph. Also did you test water params after the incident?

[Pet Detective]

Thanks Jim, I agree that the 7' is long, that is what lead me to replacing the Penn Plax Cascade filter, it was only pumping 265 GPH. The new marineland C530 pumps 530 GPH and is rated for a 180 gallon tank. My tank is 65 gallons. Since this all happened I have been running the tank with about 10 -15 tetras that I added about 3 1/2 weeks ago. I would like to restock it with Discus again, and I am currently cycling a 36 gallon quarantine tank for that. The main tank is doing well, with crystal clear water and healthy fish. I realize the set up I am using may not be what everyone is using, but I think by replacing the smaller PennPlax filter with the larger marineland would not cause a mass casualty again. The PennPlax was working fine at the same distance for the four months that I had the discus, I was just dissatisfied with food particles not filtering, and building up in the canister. I really think the catastrophe was triggered by the stagnant water in the aging tank that caused a toxic reaction in the canister filter that sat idle for about 3 hours. Then not having any aeration in the tank after the water change, the fish suffocated. I can't relocate the canister closer to the tank, so I will just need to monitor it very closely with frequent water changes and cleaning the canister regularly. I can also try the gph test you suggested for peace of mind. I can't remember what the water readings were when it happened, I may have put that on the post when I first started this thread.

[Aquaman218]

There have been numerous published studies performed, that prove BB do not die in a matter of hours. In fact, they can survive for several years under those conditions. As Iminit has stated, I have also turned off my filter several times while doing water changes, and subsequently forgotten to turn it back on. Hours later, when I remembered, I turned the filter back on with no ill effect. Also, several weeks ago, we had a power outage in the middle of the night, It only lasted an hour, but when It came back on, My Eheim 2215 failed to restart. I found it the next morning (at least 5 hours later) and was able to restart it. Again with no ill effect.

I know this isn't helpful, but I believe something else is to blame. I would suspect the tubing, the rock, or the artificial wood.

Robert