# Need help! Tetra's dying....



## yamadog (Oct 7, 2012)

So in my 135 gallon sa cichlid tank I have a school of 25 black neon tetras and a school of what started out as about 40 Serpae tetras. I have lost at least one serpae every day for about two weeks. All other fish seem fine. I do a weekly 50% water change and use an API master test kit and amonia, nitrite, and nitrate read 0. I tested twice today to verify test results. Tomorrow is water change day. I haven't lost a single black neon. Can anybody shed some light on what I may be doing wrong? The dead fish have no damage to them (I thought they might be getting picked on by my Tapajos and Pindare because they swim in the bottom half of the tank where the black neons swim up top) and I cant see any of them swimming funny or hiding out to die or..... Jason


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## yamadog (Oct 7, 2012)

Oops....Reread the instructions and looks like I was doing nitrate test wrong.....I wasn't shaking the solution bottle, I was shaking the test water. Im an idiot. Anyway, now having done the test correctly, i'm reading 10ppm. Still pretty good right? So what else am I doing wrong? Jason


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## rgr4475 (Mar 19, 2008)

Yes nitrate 10ppm between water changes is good. As far as what is killing fish, I am not familiar with Tapajos and Pindare but if there are no problems with your water, and no signs of illness, there is not much left then aggression towards the dying fish.


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## sunboy (Nov 10, 2012)

could be stress through bulling


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## Doyoulikefishsticks (Jan 10, 2013)

yamadog said:


> I do a weekly 50% water change


I think 50% weekly is too much, but I dont know about tetra's and how they can deal with it.I would say that this could be your problem.

What is your source of water for the change? Tap? Have you tested your tap water for pH, KH, ammonia, etc, with your test kit? Is it similar to your tank? Do you condition it properly before you use it? Do you let the water reach a temperature similar to your tank temperature before adding it to avoid temperature fluctuations?

Frankly, I have noticed my mbuna's freaking out occasionally after I do only a 10% water change. The water I add I have prepared ahead of time. I put 10 gallons in two 5 gallon jugs, condition it, and let sit over the course of a few days. I noticed that when I add the 10 gallons to the tank, the temperature drops 2 degrees. (I have a 75 gallon tank) so, if your doing a 50% water change, that water you add better be the same temperature as your tank, or you will have fluctuations greater than what I experience.

I would suggest not doing such a heavy water change weekly, and reduce it to more commonly accepted percentages.


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## DJRansome (Oct 29, 2005)

Not sure about CA or neons, but 50% (or more) water changes are a good thing for most Rift Lake cichlids. You do have to match your parameters definitely. And some fish are more sensitive to water changes than other (cyp fry for example).


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## metricliman (Sep 3, 2012)

Doyoulikefishsticks said:


> yamadog said:
> 
> 
> > I do a weekly 50% water change
> ...


I know people that do 100% every 3 days. Water changes are always better.


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## yamadog (Oct 7, 2012)

Yes, The water is dechlorinated tap. I use a thermometer and new water is within a degree or two of the tank water.And the problem is not just after water changes..... It's a dead fish daily. Again, all other fish( including the black neon tetra's) are fine. The school is down to 12 now.... Jason


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## Doyoulikefishsticks (Jan 10, 2013)

Interesting, well thanks for clearing that up about the water changes. I guess 50% is fine as long as water parameters are in equilibrium to the tank water.

Yamadog stated that there was no damage to the dead fish, so doesn't that rule out aggression? There must be another issue.

What about metal toxicity in the water? Is there a way to test for that? How would metal toxicity affect fish? Could they die suddenly from it without any obvious signs?

Did you get the tetra's all from the same supplier? Or somewhere else? Perhaps they are just a bad batch? That happens occasionally, I think.


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## DJRansome (Oct 29, 2005)

Undamaged fish does not rule out aggression...a fish can be harassed without being damaged and made susceptible to an illness.


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## yamadog (Oct 7, 2012)

Two more dead today..... Only 8 left. I have yet to witness any agressive behavior to these poor guys. The cichlids in the tank are all eartheaters and as far as I can tell, very peaceful. Again, ALL other fish (including 25 Black Neon Tetras) are fine. I am totally baffled.


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## Doyoulikefishsticks (Jan 10, 2013)

Might I suggest getting another tank to separate them from the other fish if it is an aggression issue?


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