# did oxygen deprivation kill my fish?



## Jeane09 (Nov 19, 2013)

he died right in front of my eyes, it was so sudden. Not much symptoms- yesterday I noticed this fish was hovering in the water, not swimming around like the others. Came to eat like normal. I tested the water- pH 7.6 (I usually have high pH), Ammonia between 0-0.25, Nitrite 0, Nitrates 5. 

Just now saw the fish skimming around right under the surface. I thought maybe low oxygen? was about to do a part wc to temporarily give more oxygen while I figure out what to do- go buy another air pump- my sponge filter is on the QT tank- but then the light turned on (timer) and the fish suddenly started rolling in the water, couldn't swim straight. I scooped it out and it gasped and died. Was that coincidence that it flipped out when the light came on?

How do I tell if it's low oxygen? The fish sometimes have rosy looking gills, but not very red. The other fish are acting normal. I have moderate amount of plants. Two things changed recently- the filter current seemed too strong, it was always pushing the fish down into the corner where it flows in, so I put a plastic baffle over the inflow. It still agitates the water where it enters, gentle ripples elsewhere on the surface. Is that not enough?

I did have sponge filter running for a while, made more surface motion, but then again the tank didn't have that for the first 2 months, they all seemed fine. And it wasn't running the last week it was in there, before I pulled it out for QT use.

can someone help me understand what's going on so I can fix it and don't loose more fish. Should I go get another airpump and put an airstone in here?


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## Jeane09 (Nov 19, 2013)

anyone can help? I just want to know what happened so I quit loosing fish- but I never saw these symptoms before. Maybe it was swim bladder problem? is that why the sudden spinning? it was literally doing barrel rolls thru the water, but looked like trying to swim upright and kept flipping over. I've cut the baffle in half- narrower now- so that there are more ripples across the water surface, but it still doesn't make strong current in the corner, push the fish down....


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## Jeane09 (Nov 19, 2013)

PS: do fish have seizures? do you think he could have gotten a sudden shock from being close to the surface when the light turned on? but I don't know why that would have killed him. I'm really scratching my head here. The remaining fish all still look perfectly fine.

I don't think my water is bad condition- the snail cruises around calmly like normal- I thought they would always climb up out of the top if a problem- do snails suffer from low oxygen would he climb up to the water line if the oxygen was low?


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## lohachata (Jan 27, 2006)

i don't think it has anything to do with o2 levels..if it did all of the fish would be gasping at the surface...it is possible that there is some kind of disease present..not sure as to what disease as that is an area i do not often deal with..i will leave that to those that have more experience..


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## Jeane09 (Nov 19, 2013)

Yeah, none of the other fish were hovering or skimming under surface like this one.

Crap. I really hope to figure out what this was, so I can treat/prevent the other fish from falling. I've lost half my danios in a week, now (but I really think the others all died from being pulled against the filter intake)

And I have otos waiting in the QT to go in here, but definitely don't want to add them to the tank until I know why the danio died.


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## lohachata (Jan 27, 2006)

your fish were weak before they ever got sucked into the filter.and the output from the filter is not enough to bother them either..
i don't think there is a problem with the cycle either but since i don't actually cycle my tanks or even take readings i am not 100% sure of that either..


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## Jeane09 (Nov 19, 2013)

But- I _saw _the outflow pushing them around. Every time they swam in front of it before, they would get swept down into the corner and struggle with their heads pointed up, until they got away from the corner. Then when I put the baffle on, they swam a lot easier, calmer, even in that corner where the filter is. 

I thought the filter was just a bit large for my tank- is it really that my fish are sickly and weak? and they've been so all this time?


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## Jeane09 (Nov 19, 2013)

And I realized there was one other factor today. I kind of forgot I had less fish now (5) I was giving them the same size pinch of food as when I had 8- they had very full bellies- probably it was a bit too much. Is it possible that the stricken fish was overstuffed, got startled by the light, lost its equilibrium right where the current was strongest and just couldn't recover because of a swim bladder imbalance? 

or am I overthinking this

if that's what happened to it, I still don't know why it would have died so quick but maybe I was hasty and didn't give it time to recover.


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## BettaGuy (May 6, 2012)

I think you are overthinking this, maybe it was a weak fish. The sudden light switch shocked it. Then you took it out and made it impossible for the fish to breathe. Could have been an issue, not sure though as I have never seen this.


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## Jeane09 (Nov 19, 2013)

Yeah, I know, I fuss too much over my little fishies! 
But, just one more question- why would taking the fish out make it impossible to breathe? I didn't lift it clear from the water in a net. I caught it in a small cup, with the water

It was a very overcast day and I didn't have a room light on, so I guess the difference between dimness in the tank and sudden light switching on could have been a big shock as he was right at the surface.


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## BettaGuy (May 6, 2012)

Oh, thought you lifted it out of the water, my bad.


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## Jeane09 (Nov 19, 2013)

No no, that's ok, and I realize now I did not make that clear in my first description of what happened. I was pretty flustered.


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## TheOldSalt (Jan 28, 2005)

Nitrite poisoning causes gills to lose their color. Check your nitrite. if you can't, then just change some water. A little salt also helps, since it bonds to nitrite and makes it harmless.


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## Jeane09 (Nov 19, 2013)

Nitrites are zero. There was trace amounts of Ammonia, no other water problem I could detect.


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