death after water change

exhumed07

Superstar Fish
Apr 30, 2006
1,774
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36
Illinois
#1
well I did a bunch of water changes today and had a few deaths. this has happened before but it's random. I use the same water from the same taps in my house from 500 feet below ground so i doubt it's the water itself. the temp dropped 1 degree during the water change so that should not have caused any issues. but shortly after the water change one of my cory cats and 4 of my neons died. once i saw one neon i sat there and watched all my fish very closely. i did not see any of the fish acting strange or eratic. just all the sudden they would float to the surface and do a couple kicks and that was the end for them. my cory fought the most but did die after about 5 min. what i truly find odd is these were perfectly healthy fish that died. i've got some very skinny sickly looking neons for some reason but they survived like nothing ever happened. has anyone ever had an issue like this before?
 

FreshyFresh

Superstar Fish
Jan 11, 2013
1,337
23
38
East Aurora, NY
#2
Ex-, I had something similar happen once in my established 20g long. One morning I found my black molly seriously bloated, setting on the bottom and a slight cloudiness to the water. Walked away to do some research, and came back a few minutes later to find her dead. My water params were 0,0,30 at the time. I did 2 large water changes and then lost a few neons and a blood-fin tetra within 12hrs or so?

Never did figure out what happened and haven't experienced anything like it since. Oddly, this was a day after my normal weekly WC and I had done a gravel vac that day. My *guess* was I stirred something up from the gravel? I dunno.
 

Newman

Elite Fish
Sep 22, 2009
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0
Northern NJ
#3
Freshy bloating sounds like bacterial infection. something it ate didn't agree with it and it got cut somewhere on the inside and got a quick infection. the other fish died maybe because of something in the water, maybe the bacteria. something weird was going on.

exhumed that definitely sounds like some chemical in the water. maybe in the WC bucket or w/e you were using, or something on your hands. SOMETHING got into the water at some point to cause those deaths.
 

exhumed07

Superstar Fish
Apr 30, 2006
1,774
0
36
Illinois
#4
Total toll was 1 glass cat 5 neons and the 1 cory cat. all this happened within 20 min of the water change. everything else is as happy and healthy as can be. even the sickly looking neons are doing fine. but like I said I've had things like this happen before. just odd random deaths after a water change. never with my cichlids though. always happens with my tropical. one thing I noticed was in the copy cat there were bubbles inside its tail. same with the glass cat. neons looked fine though.
 

exhumed07

Superstar Fish
Apr 30, 2006
1,774
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36
Illinois
#5
think i may have found out what happened. my water has alot of air in it and my hose was kinked. so instead of large bubbles it turned them into micro bubbles. even though i let the water settle out i think maybe those micro bubbles killed them.
 

Newman

Elite Fish
Sep 22, 2009
4,668
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Northern NJ
#6
never heard of bubbles killing fish =/
if you think the small bubbles may have gotten stuck on gills and suffocated the fish, i don't think that's how it works.
i may be wrong though.
 

exhumed07

Superstar Fish
Apr 30, 2006
1,774
0
36
Illinois
#7
well as i mentioned with the cory cat, it had bubbles inside it's tail and with the glass cat i noticed bubbles within it's body, within the meat of the body. as with some of my other fish there were bubble accumulating on them. I've seen the bubble accumulate on the fish before but never killed them that i know of. everything is going fine now so i really dont think there is anything toxic within the water. I'm just trying to figure out what it was that happened and that is the only thing i can think of.
 

Newman

Elite Fish
Sep 22, 2009
4,668
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Northern NJ
#9
to figure out what is causing the bubbles, in tissue (not just ON the fish right?) we have to see which metabolic processes produce gas in any form. then w/e chemical made those processes malfunction is the culprit.

The one thing i can think of that kills things really fast like that is cyanide in the water. but we don't know if that's the case here.

are you sure no weird surfactants or oils got introduced to the tank during or before the water change? like film in the WC bucket or on your hands, or w/e equipment touched the tank? Those could suffocate them too.

i am just trying to guess random things now lol
 

exhumed07

Superstar Fish
Apr 30, 2006
1,774
0
36
Illinois
#10
75% change and took about half an hour to fill the tank. I always go slow since it is dirted.

As for the fill i don't use buckets. I use a hose hung on the corner of the tank. as for the bubbles i've had that happen with guppies before. it's like they just blow up the tail and soon after the fish is dead. I'm just totally confused as to what the issue is. i'd like to avoid this in the future obviously lol.
 

Newman

Elite Fish
Sep 22, 2009
4,668
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Northern NJ
#11
i can't think of anything either. have you tried researching "bubbles in tail" before? maybe someone out there has figured it out?

EDIT:
maybe gas embolism?
Koi Diseases, Fish Disease Symptoms, Fish Disease Identification

has to do with pressure changes and nitrogen - similar to what scuba divers get if the surface too fast. would certainly explain instant deaths of your fish. but idk how pressure is involved during a water change =/
 

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Newman

Elite Fish
Sep 22, 2009
4,668
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0
Northern NJ
#12
shoot i think I am onto something.

when you take water out, maybe pressure on the fish goes down (or up idk) and then when you fill it back up there is a pressure change which causes nitrogen in the tissues and blood to become damaging to the fish, causing serious cramps and quick death.

dammit. then how do our fish handle simple water changes? I sometimes change large amounts of water and had no idea pressure affects the fish during a water change so much.

btw the nitrogen is just from regular air i think since it's mostly nitrogen. idk if fish only take in oxygen through their gills, i am sure other gasses are taken in too.
 

exhumed07

Superstar Fish
Apr 30, 2006
1,774
0
36
Illinois
#15
I'll try to research it further. i never thought about the pressure difference. but pressure changes from higher in the tank to lower in the tank. would think if they were for whatever reason uncomfortable they would move to a higher level in the tank to avoid sudden pressure increases.
 

FreshyFresh

Superstar Fish
Jan 11, 2013
1,337
23
38
East Aurora, NY
#16
I would think fish are exposed to air or oxygen bubbles all day long, be it huge or micro bubbles. Another thought is fish don't die instantly being out of the water, so I don't think they could suffocate so quickly.

Like OC suggested, it sounds more like a sudden, drastic water chemistry change did them in so quickly.
 

Newman

Elite Fish
Sep 22, 2009
4,668
0
0
Northern NJ
#19
idk either but the bubbles have to do with that. quick death too. I am sure pressure changes depending on the volume of water in a tank, and when that changes, there must be some sort of pressure swing on the system and everything in it including the fish. it's physics. though i do not know enough details to explain it.
it could be something else too.
 

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FishDad

Superstar Fish
Mar 4, 2012
1,218
1
38
Cleveland
#20
I've done 90% water changes in my 125g and never had pressure change be an issue. I would imagine its not as much of a pressure change than if a fish in the wild dives and rises a few feet.

He uses well water. Its subject to all sorts of unpredictable elements. That's were I'd put my money. Maybe test the water's hardness or ph. Tetras are soft water aren't they?