# Cardinal Tetra keeps dying



## tanin (Feb 27, 2012)

Hi Bro,

I have problem keeping cardinal tetra. They keep dying out after 1 or 2 days in tank. I usually aclimatise fish before introducing and only 3 to 5 at a time.

I have a 7 gallons tank fully cycled (ammonium and nitrite is at 0ppm). Plants and shrimp are doing fine. Current stock in tanks are molly and 2 cardinal tetra. Whenever I tried adding new tetra or livestock, they would die in a span of 3 to 4 days leaving only the current batch of 3 fishes. Most of the time these 3 surviving fish will swims amongs the plant towards the back of tank and will come out to join the new batch when they are introduced. There is no fin nibbing or aggrasive behavior towards the new fish at all.

I do inject CO2 and drop checker is not light green in colour. I do water change weekly at about 30%. I monitoring of ammonium and nitrite on alternate days and they are always fine. Do I still need to change water if these 2 parameters always remains at 0? My tank is quite heavily planted though.

Very discourage and sad to see fish die. It has comes to a point where we might switch to shrimp tank....

What could be the problem? Thanks in advance.​


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## nalu86 (Oct 19, 2010)

bad batch of fish? try buying them somewhere else.


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## tanin (Feb 27, 2012)

Can do since both times are form the same shop.


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## Psionic (Dec 22, 2011)

What are the other kind of fish? What's the temperature of the water? Mine tend to like it warmer than my normal tropical tank. 


-Val


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## tanin (Feb 27, 2012)

Psionic said:


> What are the other kind of fish? What's the temperature of the water? Mine tend to like it warmer than my normal tropical tank.
> 
> 
> -Val


 
I do not know about the temperature.

Other fish are molly and rummy nose


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## ryc120 (Jan 17, 2012)

Try turning off the co2 the day you are going to put new fish in. Slowly bring the co2 back on the next day to acclimate the new fish. 

It could be the new environment, and co2 in the tank being too much for them to handle.


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## s_s (Feb 15, 2012)

Shrimp and cardinals and mollys and rummynose? 7 gallons?

You're likely overstocked. How high is nitrate?


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## tanin (Feb 27, 2012)

s_s said:


> Shrimp and cardinals and mollys and rummynose? 7 gallons?
> 
> You're likely overstocked. How high is nitrate?


 
Nitrite and ammonia are both 0. I believe water condition is ok as the colour of both rummy nose and tetra are very vibrant. They seems to hide among the plant most of the time. I suspect they are stressed due to the strong current from the filter. I now places a spongue at the filter output to brake the current and they seems to come out more.

I am not sure the death are stress related? Any comment?

thank you


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## Diana (Jan 14, 2010)

NitrAte is different. It is not nitrIte. 

Ammonia and nitrIte at 0 ppm means the nitrifying bacteria are thriving, and producing nitrAte. 

A heavily planted tank may be rather low in nitrAte, but not always, and especially not with a lot of fish and shrimp in such a small tank. 
____________________________________________________________

Set up a quarantine tank. 
Make the water match the water in the bag with the fish: GH, KH, TDS. 
Drip acclimate the fish. 
Gradually over a month or so alter the water chemistry so the Q-tank matches your main tank.


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## tanin (Feb 27, 2012)

Diana said:


> NitrAte is different. It is not nitrIte.
> 
> Ammonia and nitrIte at 0 ppm means the nitrifying bacteria are thriving, and producing nitrAte.
> 
> ...


How will this affect well being of fish? Am I right to say that this can be overcome if the fertilizer contains nitrate?


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## trixella (Jan 24, 2011)

tanin said:


> How will this affect well being of fish? Am I right to say that this can be overcome if the fertilizer contains nitrate?


High nitrates aren't great for fish and if your nitrate levels are high it wouldn't be good to be adding more in with fertilizer. Do you have a way to test your nitrates? Cardinals also generally prefer softer acidic water. What is your ph and gh?


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## CatB (Jan 29, 2012)

trixella said:


> High nitrates aren't great for fish and if your nitrate levels are high it wouldn't be good to be adding more in with fertilizer. Do you have a way to test your nitrates? *Cardinals also generally prefer softer acidic water. What is your ph and gh*?


i'd also like to know- mollies and cardinal tetras typically live in practically opposite conditions. mollies like hard, high-pH water, cardinals like softer water as mentioned above.
also, how do you acclimate your fish? do you just float them before adding them to the tank, do you add water via a cup every so often while floating, do you drip-acclimate? or do you just take them direct from the store and plop them in the tank? if you're not acclimating very well, especially with CO2 in your tank, then that would explain the die-off.


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## s_s (Feb 15, 2012)

tanin said:


> I believe water condition is ok as...


Hubris. You keep killing fish, something with the water condition is most likely *not* OK. Let's get past this, eh?



tanin said:


> They seems to hide among the plant most of the time. I suspect they are stressed due to the strong current from the filter.


Or they are stressed because of high nitrates.



tanin said:


> How will this affect well being of fish?


Cardinals are fairly sensitive to high nitr*a*tes. It would kill them (as you have described, which is why I mention it). They are notoriously hard to breed, and as such most specimens for the hobby are wild caught. This makes them the most sensitive to nitrates of the fish you've mentioned. So a nitrate spike would kill them first (as you've described).

How often do you do water changes? How much of the water do you change each time?


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