My fish keep dying. Could GH/KH be the problem?

[mtncrux]

I have a 10 gallon tank that has been running for about 9 months now and has given me no end of problems.

I keep the tank lightly stocked :2 guppies, 4 cherry shrimp, and a small army of pond snails at any given time.

I have a API master test kit (liquid) and regularly monitor my water quality. Ammonia and NO2 are always 0, NO3 is always < 5ppm but I keep having fish die.

I fell like I am doing everything right, but fish keep dying.

I think I may be onto a clue. I just tested my water hardness using an API GH/KH test kit.

The tank KH is 3 degrees (3 drops of solution before color change)
The tank GH is off the chart of the API test kit. It took 13 drops of solution to get the color change which means than the GH is > 214ppm.

Tank PH is 7.4

I tested my tap water and got a KH of 2 degrees (2 drops of test solution) and a GH of 35ppm (2 drops of solution). I was very surprised that my tap water and my tank water were so different.

It has been 1 week since my last 30% water change.

So, my questions are:

1. Could the high GH be the reason that I have had so much trouble with this little tank? Over 9 months, I have managed to kill 5 guppies and 9 pygmy cories. (not all at the same time, I never had more than 3 guppies at a time. I kept stupidly replacing them then they would die after a few weeks/months). The last two guppies that I lost died two days after a water change. Ammonia, NO2 NO3 levels were all 0 when the fish died, but I didn't think to check GH/KH. It does make sense that if they were used to the hard water, then doing a water change and severely lowering the hardness might have killed them.

2. Why does my water get hard after it has been in the tank? I do not have any rocks in the tank other than the gravel. The decorations consist of some driftwood and some plastic decorations from PetSmart. I have some lie plants in the tank, but I can't remember the name of them. That seems to only leave the gravel as the culprit. The gravel does not look like limestone. The gravel is some sort of small light colored (white/grey/brown) pebbles that I bought at petsmart when I setup the tank.


3. What should I do? Do I need to remove the gravel? I like the look of gravel, so how do I make sure the new gravel doesn't also raise the hardness?

I think that the next time I do a water change, I will test hardness daily and see how it changes over time.


Thanks for your help.

-David

 

[mtncrux]

I decided to test my current gravel. I put a few net fulls of gravel into a tupperware container and put in 2 quarts of tapwater. I will test the GH/KH daily and see if the hardness changes over the course of a week. If it does, then I guess I need to find a new substrate.

 

[Pezzep]

Both my kh and gh take about 17 drops to change the colour and my fish are doing great. Are you treating your water before adding it with some sort of dechlorinater? When adding new fish do you acclimate them? When doing a water change do you keep it at about the same temperature as your tanks water when adding it?

 

[20cc]

Both my kh and gh take about 17 drops to change the colour and my fish are doing great. Are you treating your water before adding it with some sort of dechlorinater? When adding new fish do you acclimate them? When doing a water change do you keep it at about the same temperature as your tanks water when adding it?

dechlorinator was my first thought

 

[Rivercats]

I've kept a lot of species in tanks with a GH of 13 without incident. Guppies, like most livebearers do best in hard water. I seriously doubt that is your problem. Are you getting all your stock from the same store? Have you considered the guppies could just be a result of poor genetics? As for pygmy cories can be alittle more sensitive to hard water but again most acclimate. I think you have something else at work here.

 

[mtncrux]

Yes, I use Tetra Aquasafe on my tap water, and I always make sure the new water is the same temperature. I usually put tap water into a food grade 5 gallon bucket, check the temperature, add the dechlorinator, give it a good stir, then I vacuum my gravel and then add the new water. The water usually only sits for the time it takes me to vacuum the gravel.

I always acclimate my fish very slowly. Float the bag for 15 minutes, then replace 10%-20% of the water in the bag with tank water, wait 10 minutes, then repeat for about an hour.

Some of my fish have died when new, or immediately after a water change, but most of them have just died for no apparent reason after living happily in the tank for weeks or even months. I have never had any ammonia/nitrite/nitrate spikes.


So it sounds like the water hardness is not my problem. If not then I am at a loss for why I keep having so many problems.

My first two fish (guppies) came from Petsmart. One of the first fish got bloated and died within the first week. After that I started buying from a very nice local fish store. All of the subsequent guppies and cories came from the same LFS.

Is it possible that those first Petsmart fish had some sort of disease that has been lurking in my tank ever since?

Oddly enough, the only fish in my tank to have survived for the entire 9 months is one of the original petsmart guppies.

 

[BBradbury]

Hello Dave...

Small tanks are a challenge for even the experienced water keeper. That's because there's very little water to dilute even a small mistake in tank management. The water chemistry in a small tank can "go south" on you in a very short time. Floating plants like, Anacharis and Pennywort will help level the water chemistry and changing and replacing half the tank water every few days is a must. No slacking! Livebearers, like Guppies will do a bit better with a teaspoon of standard aquarium salt added to every 5 gallons of the new water.

Again, 50 percent water changes every few days. If you can change more and do it more often, your fish, in such a small tank, will appreciate the pure water.

B

 

[Pezzep]

I have two small tanks and I don't need to do that many changes...I do 50% once a week and my tanks are fine, I found when I did 50% every other day on my rcs tank it stressed them and caused them to die off ever since I stopped doing 50% every other day they are living, I do top offs when needed on the shrimp tank and 25-50% every two weeks, they are less bioload tho...in my other 8gal there are 5 neons at the moment when I bought them didn't notice they had ich (stupid me shoulda knew they were on sale for a reason) so now I have the tank set to 88 degrees using aquarium salt to treat, and do a 50% once a week none have died yet had them for a week and a few days now, all the spots have cleared up just waiting for the ich to die off in the tank and make sure they don't return. Maybe I'm just lucky though.

 

[aqua_chem]

I am in agreement that your chemistry probably isn't the problem by itself. However, the GH swing might be problematic. If you're having a 200 ppm change, that could possibly be a problem, although if anything could take it, it would be a guppy. Let us know how the gavel-tupperware experiment goes. Also, how often do you normally do water changes, and how much?

The other thing that this may be is an insidious disease like 'Fish TB' that can lurk in a tank for long periods of time without symptoms. Have you noticed any peculiarities with the fish before they die, such as funny swimming, bumps/sores, lethargy, seemingly bent spines, or paler/darker coloration?

 

[mtncrux]

I do a 30% water change every two weeks. I check ammonia, nitrite and nitrate weekly and I have never seen nitrates over 5ppm.

I just did a 30% (3 gallons) water change and checked hardness before and after:


Before: KH = 3degrees, GH = 215ppm

After : KH = 3 degrees, GH = 162ppm

Could a sudden drop of 50ppm cause any problems?


I am starting to think that the hardness is not my problem.


I have not noticed any pattern of illness in my fish. The pygmy cories all went the same way. They would start out perky and happy, then they would stop eating and get more and more lethargic. After 1-2 weeks they would just lie on the bottom with occasional bursts of frantic swimming in circles (upside down, sideways, etc). Some of the cories lasted for 2 months. They did not die at the same time, but they all went the same way. Over a two month period I kept going back to the LFS to replace the cories when they dies (keeping a school of 5) and the same stock were thriving at the LFS over this same period.

One of the guppies had no tail when I found it, but I hadn't noticed any fin problems so the fin may have gotten eaten by a shimp after the fish died.


The only common factor in the guppies is that I have had three guppies that have been moderately bloated at some time.

The very first guppy to die got bloated immediately (was probably sick from the pet store) and had trouble swimming, then died.

One of the guppies that is surviving went through a period where it became very bloated and was spending all of its time at the surface. I started feeding it peas and the bloat went away and that guppy is now fine.

Another guppy was bloated for 2-3 weeks, then it recovered and was fine for three months and then dropped dead two days after a water change.

I have taken some of the fish to my LFS after they died and the LFS couldnt see any problems. I also had the LFS test my water and their numbers matched mine so I know my test kit is OK.

I am starting to think that maybe there is a lingering disease or bacteria in the tank. Should I try mediating the tank? Without a more diagnosis I wouldn't know what to use.

Thank you all for your help and advice.
-David

 

[20cc]

maybe you have a disease in your tank . the missing tail sounds like fin rot .if one fish died then they all got it . you should inspect your fish for parasite or bacterial infection.

P.S you should always quarantine fish you buy from a chain fish store , there fish are almost always sick .