Can you explain all the steps that you did from the time you brought a new bag of fish home from the shop?



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.

Can you explain all the steps that you did from the time you brought a new bag of fish home from the shop?
LIFE IS UNBEARABLE WITHOUT A FISH TANK!!!

Can you explain all the steps that you did from the time you brought a new bag of fish home from the shop till the time they are in your fish tank?
LIFE IS UNBEARABLE WITHOUT A FISH TANK!!!



1) Drive home with bag on floor with stuff to stop from rolling. (noticed that fishes loose colour at this point)
2) Float in a pail of water for an hour plus, bag remains unopened
3) Open the bag and remove some water and float in tank for at least half hour. (colour of fish gets more bright now)
4) scoope a small amount of water from the tank into the bag, much less than the balance in the bag
5) after 10 minutes remove some water from the bag and add more water from tank. wait for 20 minutes and scoope fish into tank
after this the fish seems normal (behaviour and colour) and the existing fish doesn't attack them.
I noticed that they are breathing more heavily than those existing ones. I have CO2 injection though (Drop checker still light green)
Before this whole process I did water change because of major readjustment. For water change I use my water filter to remove chlorine through activated carbon, did not add any anti-chlorine.
I am using internal overflow filter.
Thank you. Kindly let me know where did I do wrong.

Since you have taken the correct steps and precautions as you have explained, there should have beeen no problem. Since you are not using a hang-on filter and I have zero experience with internal filters, I am unable to help. I only have some experience with simple hang-on filters.
Just wait a while for other help on the way.
LIFE IS UNBEARABLE WITHOUT A FISH TANK!!!



Do I still need to add anti-chlorine if I am using filtered water?

Are you able to post a picture of your tank?
LIFE IS UNBEARABLE WITHOUT A FISH TANK!!!

Bro, i am not sure how much chlorine your fiter can remove... Some filter are not very effective except for filtering rust or debris. Note that chlorine levels in some housing areas are higher.
Better get some anti chlorine. Cheapo ones are better than none, got budget go for seachem prime
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Link to my Blog
I am not PERFECT but I am LIMITED EDITION !!!BIG Tank comes with BIG Responsibility...as they makan a lot of $$....lol

No that is that is the killer touch

Bro I suggest you state your full tank specs here for us to investigate, is your temperature normal 24-29? Do you dose liquid fertiliser, how is your bio load?






Chlorine and Chloramine cannot be removed by activated carbon. However, given time for the water to stand, chlorine will leave the water body, whilst chloramine will remain.
It is important to get a good water conditioner. Also, monitor your nitrates since your ammonia and nitrites are both at zero, you shouldn't really be bothering with them.



Can I add anti chlorine directly into tank or should I do water change again?





Can you describe where you got your cardinals (Which Shop) and what is the condition of them in terms of color vibrancy.
Any PH indication at the shop?
Any lost of colors, dead fish in the tank before you buy.
For this shop, usually what is the arrival time of fish restock compared to the time you buy?
Based on your description, I can only tell that the fishes arrived in total shock.
When you buy it back, I do not see why the pail has to come in. Usually I would place the fish plastic (unopened) directly into the water surface where it floats and meantime, the temp in the bag syncs with the temp in the tank. Regarding opening, the mouth of the plastic usually face downwards so the fish swims out on their own instead of me catching them.
1. Dechlorination is advised. AP (Aquarium Products) Genesis $3-6 per bottle, just a few drops. 1 drop per gallon. Treats 2000 gallons.
2. If fishes are not in good condition, you are advised to quarantine them first before introducing into the main tank using the correct medicine in a separate tank. Simple fish tank, filtration media, plus air pump will do. Usually people uses the water from the main tank so the fish have time to adjust. As long as it is not tetra disease. Which has a high kill rate and low survival rate. You can google for this if you are interested.
Awaits your reply.





Generally, there are few ways to use De-chlorination solutions.
1. Fill a pail with water, drip drip, wait for 1-2hr and use a air stone to oxygen the water. Once happy, start to introduce the water. You can add your plant food and fish vitamin at this point too if you like it. You can use hand as a stirrer.
2. Fill a pail with water, gradual pouring into the tank, (please use a plate and pour onto the plate, can use another cup too) drip drip solution. Now your fishes have to be really used to this kind of regime before you can attempt this. In this case, it is uneven as it depends on the water flow to get around the tank.
3. Consider getting your fish source from another shop.
4. If fish arrive on Friday, don't visit the shop on Saturday. The fish haven't even settle down from the farm, let alone your tank. If you visit on Tue, most likely stable. If you go Thursday and no more left, tell yourself just too bad and wait another week.



Last edited by hardric; 30th Mar 2012 at 20:32.
More than ONE fish = Fish
More than ONE species of fish = Fishes



First I buy from the shop which i believe is frequent by many of the member here. Fishes are in good condition and no dead fish in tank.
I do not think the source is the problem and after reading I believe it is caused by my own ignorant. The fishes have been there for quite sometime and new batch just arrived on the same day of purchase. They have not added to the existing stock.
My thoughts of activated carbon removes chlorine is because the manufacturer stated that with test result.
I really appreciate all the helps and advise given. Thank you



So it is best for me to change water which has be treated with anti-chlorine rather than adding directly into the tank right?





1. Follow what you think right now. You can change water at will, but have a bit of patience to wait.
2. You should take the chance to dismantle the filter and dismantle every part and wash as best as you can. If you do not have a decent brush, use tooth brush first.
3. See if you can remove the active carbon or not as well. Active monitor next morning on your fish condition as well. You should fine tune the temp of the water from pail to be similar to the tank as close as possible. New water lacks oxygen. So do not suspect it is your CO2 problem. Rest of the stuffs if you need to buy, try to get it tomorrow. You can't do much now.
Unless you have a car, then can drive to Clementi Polyart since they are open 24/7.




I had a similar experience specifically with cardinals. You not so bad still can last 2days. Mine will be gone in less than an hour. I am using a pressurised co2 system and indicator is light green. Suspected could be due to CO2 poisoning. But since the other fishes are doing ok have to rule out the poisoning. Maybe they need more time to adjust to the new water chemistry. The next time, I tried introducing the cardinals in the morning when co2 level is depleted. All five survived. Its been a month now and still counting. It could have been a freak result though. Just to share![]()
3ft Tank. Eheim 2028. ADA soil. LIghting 2 X 39 T5 / pressurized Co2 @ 8hrs/day.
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