[Mistral]

With years of aquarium experience with African Cichlids and some community tanks I decided a few months back to try a more heavily planted tank with higher lighting and pressurized CO2.

After some struggle I have finally got a healthy and lush looking carpet of HC (Dwarf baby tears) growing with now almost 70% of my 10 gallon tanks floor covered. The problem is I really dont know at what levels to maintain my CO2 output at with 30 watts of 6700K lighting? The plants are doing well. But the 8 cardinal tetras were struggling today after a water change and 2 began darting all over and swimming in odd attitudes until one finally died. I immediately did a 50% water change and they all have seemed to stabilize since.

Upon changing the water I'm still getting some cloudy water for a couple hours indicating a mini cycle that I'm aware of and keeping a close eye on. I also added half a capfull of Flourish comprehensive plant supplement followed by the same dosage of Flourish Excel during the water change.

Again, the plants are thriving and pearling and I currently have my bubble count at around 2 per second, but the fish all almost died on me tonight about 2 hours after a water change. Could it be related to the plant supplements or C02 output being too high or somthing else?

Cichlids were just so much easier to take care of!!

 

[tetra73]

Did you check your ammonia and nitirate readings? If your tank is going through some sort of mini cycle, these reading will experience a spike. Excessive CO2 does not cause your fish to suddenly dashing around. You may begin to see them swimming near the surface and breathing very rapidly.

 

[rocketdude1234]

How much of a water change did you do to begin with? Were the parameters matching those of the tank? What about the temperature? Was there something in the water you may not have known about?

If plants are pearling and fish aren't showing signs of oxygen deficiency I'd say your co2 levels are okay.

I personally never notice fish darting around and dying as a result of Flourish Comprehensive or Excel even at 2-3x the recommended dosing.

 

[Mxx]

I think there is something about ammonia being not so toxic in acidic water, but quite toxic in alkaline water. So if you did a water change which suddenly resulted in your water becoming alkaline, then that ammonia may have converted to the toxic form, and thus immediately killing your fish... Research that for a more concise explanation than what I gave, but it sounds as if that is what might have happened.

 

[Mistral]

Thank you all for the informative replies. I was honestly suspect of the Flourish comprehensive supp but that seems to be unlikely now and I do remember the fish breathing fast with a few near the surface but while doing so they were swimming very poorly and looked as if they had a swim bladder issue rotating on their sides and going nearly vertical up and down. Does this sound like ammonia poisoning?

This issue happens only after a water change, but I've always added the fertilizers along with tap water conditioner to the new water so I couldnt really rule out the ferts I've been adding. I've honestly not been checking my water values and just used common experience to keep my water clean as I've never lost a single cichlid in the past 5 years. Well I guess this isnt a cichlid thank though..

I will follow up more on the comment made by Mxx and do some research. But off hand, do you know the best way to prevent these spikes during a water change? I've always thought that doing a water change was only good for the tank as long as not too much good bacteria was removed at the same time? What can I do to prevent this problem on my next water change? I'm heading out to get a water test kit tomorrow and feel ashamed I haven't been using one.

 

[Hoppy]

Did you use Prime or another dechlorinizer when you did the water change? That would cause problems if you didn't.

 

[Mxx]

Well you shouldn't have ammonia in your tank, if that's what was causing the problems. But you'll need to test your water to find that out. Either your bio-filtration or your plants should be able to absorb all your ammonia quickly, unless you don't have enough bio-filtration or plant mass in comparison to your fish population and feeding amounts. You didn't mention your filtration, but upping that should solve an ammonia problem, so long as you don't of course do things like cleaning your filter media with chlorinated tap water.

 

[Mistral]

I use a penguin Bio wheel 100 which I believe is rated up to 20 or 30 gallon sized tanks and mine being a 10 gallon. And I currently have 7 small cardinal tetras, a ghost shrimp and otto catfish. The tank is 70% thickly carpeted with healthy looking HC. It seems everyone thinks it has nothing to do with my plant ferts or C02 and as you said Mxx possibly related to a PH spike allowing harmful transformation of ammonia. I'm basically afraid to do a water change now on this small tank because the fish seem stable and happy until I do so. I have been using Nutrafin Aqua plus water conditioner and never had any problems for years.

Just to recap, I did a 20-30% water change with obviously tap conditioner added to the water as well as Flourish Excel and Flourish comprehensive plant fertilizer. About 30 mins after the change, the tank was only slightly cloudy indicating a mini cycle and then began clearing within 1-2 hours after. Then around 2 hours after the water change, the tank was basically clear but half the tetras began swimming in sharp odd bursts in all angles looking like they had a swim bladder issue resulting in one death. I luckily caught it and immediately did a rapid 50%+ water change and all the fish stabilized within 10-15 mins and all appear still healthy today. The tank did not show any cloudiness at all after the second larger water change and I only added water conditioner the second time around as also turned off my C02 supply. I woke up this morning turned on the lights/CO2 and made the usual dose of flourish excel and all is fine.

If anyone can pick out exactly what may have happened please explain. Heading out to get a water test kit now!

 

[Hoppy]

If and when you discover what the problem was, be sure to post a followup. I'm stumped so far.

 

[Mistral]

Three days later and all is well. Fish happily swimming, plants pearling and water conditions looking good since I've started using a test kit to check the parameters. My next water change is only a few days away and thats when the scary part begins. I'll be checking my tap water before its added to the tank to confirm its similar if not the same.

 

[audioaficionado]

Did you use Prime or another dechlorinizer when you did the water change? That would cause problems if you didn't.

Another thing to consider is that municipal water can be occasionally super chlorinated with higher amounts of chlorine/chloramine to help keep the pipes clear of bacteria. I always add 4x the amount of dechlorinator during water changes just in case my tap is super chlorinated at the time.

 

[tetra73]

Three days later and all is well. Fish happily swimming, plants pearling and water conditions looking good since I've started using a test kit to check the parameters. My next water change is only a few days away and thats when the scary part begins. I'll be checking my tap water before its added to the tank to confirm its similar if not the same.

You can also get a "water bucket," I have a 18g plastic storage bucket, to age your tap water before doing the water change.

 

[Mistral]

You can also get a "water bucket," I have a 18g plastic storage bucket, to age your tap water before doing the water change.

Filling my bucket up tonight for a water change on Sunday.

 

[tetra73]

Filling my bucket up tonight for a water change on Sunday.

Makes sure you keep the water aerated with an air pump..

 

[DarkCobra]

One capful = 5ml of Excel.

That is the Seachem-recommended initial dose for a 10G, or 5x the daily dose.

However, I personally feel the recommended initial dose is too much, too fast, and have always avoided it. Instead I use only 1ml/10G daily, sometimes more if I'm treating for algae.

Now while I'm not sure if the Excel is to blame in your case, I do know this:

If a superchlorination event, rise in pH with possible ammonia toxicity, difference in TDS or temperature, lack of dissolved oxygen, or any other factor from your tapwater had been responsible, then the second and larger water change only two hours later would likely have killed the cardinals stone dead, not saved them.

 

[audioaficionado]

Unless the super chlorination had flushed out of his mains by then. Very bad timing is need for this to happen, but it's not impossible.

 

[Mistral]

The second water change basically saved the fish, with one fish probably checking out in the next 2-3 mins had I not flushed the tank with the 50% water change. As I said in my previous post, 2 days after this event all was fine until this morning when I woke up and found another dieing tetra swimming in a very bad way.

Was it the fish that I almost lost 2 days ago that finally gave in today due to stress, I dont know? But all the fish had been equally feeding very well and showing active, healthy behaviour and colour over the past few days.

I did a 50% water change today and its been pretty uneventfull thus far except one or two of the tetras not really swimming with the rest of the school so I'm watching these fish closely even as I type this.

I compared the water conditions of my tap water and the existing tank water and no variation is shown. These cardinal tetras are captive bred in Toronto where I live so they should be very comfortable with this water I would think.

Also, so far no sign of any mini cycle in the tank after this fairly major water change. I know this is a smaller tank and maybe it wasnt fully cycled like I had thought before adding fish, but I thought cardinal tetras were pretty hardy? Can anyone recommend a tough tetra species or other small fish suitable for a small 10 gallon tank? I don't plan on losing any more fish but at this point anything can happen. Also, I have a ghost shrimp and a otto catfish and they have never seemed to show any ill effect to the water conditions and I always thought shrimp were pretty sensitive compared to cardinal tetras.

 

[Mistral]

Here is the tank with the 6 out of 8 remaining survivors. Its pretty unorganized, but my main priority has been growing the HC which has been pretty demanding!