Lost Fish

[Rhindon]

I'm not sure what happened. Riding out a mini cycle, I did a water change yesterday. Within 5 minutes of putting everything back in place, I had three dead Glofish. I lost another overnight. Before this started, I had 8, now I'm down to 4.

Here are my stats since I "inherited" the tank:

Date Time pH Ammonia Nitrite Nitrate H2O Chg? H2O Chg % Vacuum Gravel?
7/26/2009 PM 7.4 0.25 0.00 15 N N/A N
7/27/2009 PM 7.4 0.50 1.00 20 Y 50% Y
7/28/2009 AM 7.4 0.50 1.00 10 N N/A N
7/28/2009 PM - 0.50 0.00 - N N/A N
7/29/2009 AM - 0.50 0.00 - N N/A N
7/29/2009 PM 7.4 0.50 0.00 0 N N/A N
7/30/2009 AM - 1.00 0.00 - N N/A N
7/30/2009 PM - 1.00 0.00 5 N N/A N
8/2/2009 AM - 0.50 < 0.25 - N N/A N
8/2/2009 PM 7.4 0.50 < 0.25 10 Y 50% Y
8/3/2009 AM 7.2 0.25 0.50 5 N N/A N
8/3/2009 PM 7.4 0.00 0.00 5 N N/A N

 

[OldMan47]

I would say that you are lucky to have any surviving fish in your tank. You need to do large enough and frequent enough water changes that both the ammonia and nitrites stay below 0.25 ppm at all times. There are several days that yours got to 1.0 on ammonia and even a few where the nitrites got that high. Do not add back any fish, feed only a small part of what you think you should and get busy doing water changes more often. Do not forget to temperature match the new water and treat it with dechlorinator.

 

[Rhindon]

The glofish were in my old tank that had high nitrites.

I have a water changer that hooks into the sink that I got when I got the larger tank. I put dechlorinator in while I was adding the water back in. It just seemed odd that three died right when I did the water change and I can't figure out why.

The ammonia level in my tap water is 0.50. The ammonia and nitrites seem to be at zero now. I am hoping they will stay that way.

 

[OldMan47]

If you were changing water on a very high nitrate tank, the low levels in the new water can also take its toll. It is best to change things slowly on a tank so that you don't shock fish. The reason that we don't worry about big water changes is because the water stays pretty good except for minor traces. A tank with really high nitrates often has a lot of mineral buildup too. It is the minerals going away all at once that is hard on the fish.

 

[Rhindon]

It was high nitrites. Would the same apply?

 

[OldMan47]

I must have misread that. The high nitrites themselves are fish killers. I would have expected the water change to make things better, not worse.

 

[Rhindon]

Ok. Those glofish lived through 1.00 nitrites. Water changes would help for a couple of hours but the tank they were in was just too small. That's why when my mom offered the 37, I jumped at it. Nitrites have been better in this tank. I just can't figure out what killed them and think it has SOMETHING to do with the water change itself since three of them went right away. I thought I matched the temp pretty well.