Cardinal tetra death

[msharper]

Hi everyone, I'm new to this forum and have been reading all kinds of threads and learning as I go. Great wealth of information on here! I am in the process of setting up my first discus tank and of course have made my life more difficult by attempting a planted community tank.:)
I have been running the tank for about three months (cycling) I first started with guppies, 20, just for the cycle and then increased the water temp. to get ready for Discus. A week ago today I returned the guppies to my supplier and purchased 25 Cardinal tetras. I had done a 30% water change before putting them in the tank and I just did another 30% water change yesterday. Almost instantly two Cardinals started swimming at the surface and I knew death was coming soon. When I woke up this morning 3 Cardinals were dead. The remaining 22 seem normal and healthy. My first thought was something wrong that I had not noticed when I first purchased them. ????? I purchase from a very reputable supplier who QT's all there live stock for 2 weeks before selling, so I question that logic. I am not new to the hobby and was doing a water change as usual. i.e. "PRIME", matching water temp. etc. My PH is 7.4 in the tank and 7.4 from the tap. Could Cardinal Tetras be sensitive to something else, KH, GH ??? Does anyone have a clue. I don't want anything like that happening with the Discus and it's for that reason I am starting out slow with the Cardinals and some Corys. And working out any kinks in my set up.
Thanks to anyone who could help me out.

[TURQ64]

Welcome..To answer a question, yes, hardness does matter..Many believe that TDS is more important than PH...I generally try to match my TDS, and then plop the fish without worry too much about PH...my ph elevates with an increase in TDS. Perhaps you should fill out the sticky questionaire in the 'sickness' section..Gary
http://forum.simplydiscus.com/showthread.php?38545-Disease-Questionnaire-please-complete

[msharper]

DISEASE QUESTIONNAIRE


Problem

1. Please explain the problems with your fish/when and how they started

No deaths over the past week, no signs of parasites, no signs of ick or other such common problems. I am quite certain I did somthing during the water change.



2. Symptoms (i.e. turning dark, excess slime, not eating, clamped fins, flashing, darting, clamped gills, white/yellow/green poop, hiding, headstanding or tailstanding, white on tips of fins, rotting or fungus, blisters/ white zits on fish, bloated, cloudy eyes, wounds)

Only two out of 25 tetras started swimming near the surface bobing around with there head up and tails down.




3. What medications/ treatments that you have already tried and results. Include dosages and duration of treatment.

N/A



Tank/Water

4. Tank size and age, number and size of fish
90 Gallon, 3 months, 22 Cardinal Tetras and 9 assorted cories


5. Water change regime/ how long has tank been running/ bare bottom or gravel/ do you age your water?
Once a week 30% not aged straight from tap (treated obviously), 3 month cycled, Pool filter sand/crushed rocks


6 Parameters and water source;

- temp __84F___

- ph __7.4___

- ammonia reading __0__

- nitrite reading __0__

- nitrate reading __0~5__

- well water __NO__

- municipal water __YES__

7. Any new fish/plants added recently
The Cardinals 7 days ago (They were in QT for two weeks before)

[TURQ64]

Sorry, repost this in the 'sickness' section!...Gary

[msharper]

Thanks Gary. How do you go about matching your TDS?

[msharper]

Just found this in the post under mine. Could this possibly be the cause? Why would only three fish be affected, were they weaker to begin with maybe?

"BTW, Prime, Safe, sodium thiosulfate and just about all the dechlorinators will take out oxygen from the water. So water with low oxygen to start with, overdosing on dechlorinator, and high temperatures could lead to a low oxygen environment anyway.
Eric"

Matt.

[TURQ64]

I use RO mostly, so I have a collection of RO reject water...the reject TDS is 880, hugely high, so each gallon I add to say a 75g tank raises the TDS 20 points...Without RO there are things like baking soda and ice melter for driveways (Calcium Chloride). I also use seachem Reef Builder for calcium...do a search here, I'm sure many answers will pop up. Were all of the Tetra deaths right after introduction, and are the remainder doing o.k. now??

[msharper]

Well over night I suppose. I did the water change at around 1:00pm and noticed the change in activity in just 2 fish around an hour after. When I woke up this morning, 3 deaths. The remaining 22 are swimming in a nice tight school all around the 90 gallons. They look great and perfect in every way.

[TURQ64]

At this point, I'd have to toss a guess towards something about the WC, as mentioned, possible chlorine/chemical issues in the method. Do you have a way to age water so thing's can gas off under aeriation?..tub, bucket, barrel? Maybe another local forumite from Montreal can chime in with a little more local knowledge on the water supply...

[msharper]

Yeah I think I will age my water. It seems more safe that way. I will be able to have all the water parameters perfect before putting the water in the tank. I had always heard Cardinal Tetras were sensitive to water chemistry change but never imagined they would be sensitive to this point. Has anyone else had trouble with random Cardinal die off?

[TURQ64]

My Cardinal die off is from my Heckel's; they've eaten all but one!....Even with aging, still add Safe or Prime at the WC...

[msharper]

Cheers, will do. Thanks Gary

[MKD]

This happened to me before. I bought a whole bunch from dog/cat pet store, but they have tiny corner for fish about 8 small tanks. Those tetra were fine in there for a month or more. I brought them home put them in QT tank and ended few of them death. Once other time, i bought a few from local friend who has them for a year. I bought them home and did not acclimate them just put them in QT tank. They all laid on their side at the bottom of the tank and just a few minutes later, they all got up and swam normal. so i guessed some of they did not acclimate to your water paremeter.