Fish dying for unknown reasons.

[uncleowenrip]

I have a 6 gallon eclipse tank with 3 CPD's, 3 Ember tetras, 2 Oto's, and 2 snails. It has been established for about 6 months now. I recently added 6 more Neon tetras to the tank, and about five days later one Ember tetra and one CPD is dead. I haven't seen one of the Neons either, though the rest of them are schooling together. So I don't know if he is dead or alive.

I checked the water perameters and the ph is about 7.5, nitrates and nitrites are 0, and the water is very soft. I then did a 75% water change and raised the temperature to about 80 degrees F (It was about 78 before). I also added a small dose of Melafix, just in case.

Any ideas what could be wrong?

 

[justonemoretank]

Why are nitrates zero? This is very, very strange. I have only approached zero nitrate, in my time of fishkeeping, in my Betta tank. It's a five gallon, with one fish. However, this is a different situation, because your tank is overstocked. These fish should be producing plenty of waste for the beneficial bacteria to turn into nitrate.

What is your ammonia level?

Are you using test strips? If so, you should consider making the change to liquid tests. They're much more accurate.

Things happen very, very quickly in small volumes. After decor, some space at the top, and substrate, you've got five gallons of water in your tank, max. Therefore, you've got to stay on top of testing and not take risks when it comes to stocking (which, IMO, you have) in order to make this work for you and your fish.

I'm worried that the test is bad if it's showing zero nitrate. You might want to get your water tested by someone with liquid tests, like at the LFS. Make them tell you numbers, though, don't allow them to say "Your water is fine" or "Nitrite's a little high."

There are other things that could be going on here. The addition of the tetras (I'm assuming they weren't quarantined, but I could totally be wrong) could have introduced a parasite. But, this is far less likely than the problems you're seeing being related to water quality. I think we should start there.

 

[Dominuslive]

It could just be oxygen starvation. Water when warm holds less oxygen, when u approach 78 and 80 degrees you help fight parasites, but you also make the fish work harder for each breath.

 

[~ocean]

check the tank parameters...

~ocean

 

[Cichlaholics Anonymous]

definitely double check those nitrates using a different test, that result does seem odd