My loaches have died and my catfish isn't looking too great

[DaveAndLiz]

I have a 60 litre freshwater tank and in the past 2 days both my loaches had died suddenly.

The tank currently contains 5 Zebra Danios. 6 Neon Tetras, 2 Black Neon Tetras, 1 Male fighting fish, 1 Black Molly, I White Molly and I Albino Catfish. All the fish are less than 4cm with the exception of the loaches which I lost.

I did a water test 2 days ago and got the following results:

pH 7.8 (tap water 7.2)

Ammonia 0-0.25ppm

Nitrite 0ppm

Nitrate 40-80ppm (tap water 10-20)

On recommendation from my pet shop I did a 50% water change to sort out the levels and everything appeared fine.

Last night my smaller loach was lying on his back and breathing very very slowly to the point that I assumed heas already dead. I placed a net around him so the other fish couldn't get to him and he died during the night. When I looked in the tank this morning my larger loach was also lying on it's back dead. I inspected the fish and found no visible sign of problems but I have never done this before so could possibly have missed something.

Now my albino catfish seems to be moving very slowly and spending a lot of time sitting doing nothing. I'm slightly worried that he might have the same problem. However, all the other fish seem absolutly fine and very active.

If anyone could help I'd be very appreciative. I hate to lose my fish.

 

[Devilishturtles]

What did you use to test your water with(liquid kit, test strip), and how long have you had the fish in there?

If you just added the fish, it could be a number of reasons.
If you have had them in there for a while, could be a whole different set of reasons.

Let us know.

 

[DaveAndLiz]

I used a liquid test kit to check the water.

I'd have the larger loach and the black neons for about a year, the smaller one, the mollies and the fighting fish about 2 months. The neon tetras and danios were added less than a week ago. Unfortunatly I've just come in from work to find another of the Danio's had died. I originally bought 5 danios a week ago, lost one and had it replaced, lost another and had it replaced and then lost the one tonight. I'm about to do a complete water test again so i'll post the current results here.

 

[Essayons89]

Hi DaveandLiz,

There are a couple of things that stand out at me when looking at your water parameters. The first is that the tank is stocked pretty heavy which is accounting for your ammonia reading. I believe that your tank comes out to 15 US gallons. Smaller tanks like this can be less forgiving when there is a problem with water quality(such as ammonia, nitrite and nitrate poisoning) than a larger tank is, especially if the tank is overstocked.

Ammonia is toxic to fish at .25ppm and above. You pH isn't very high but it is an alkaline pH and ammonia is more toxic in an alkaline pH than it is in an acidic pH. You don't have any ammonia in your tap do you?

The second thing that jumps out at me are your nitrate levels, they are too high. This problem is compounded since you already have 10-20ppm of nitrate in your tap water. For fish to stay healthy nitrates should be kept below 20ppm, ideally between 5-10ppm, the lower the nitrates the more your fish will thrive.

What sort of water conditioner are you using? You are going to need to treat your tap water with a conditoner that also neutralizes nitrates. Amquel Plus is the first product that springs to mind. This will also neutralize ammonia but won't interfere with biological filtration.

How often do you do water changes and how much water do you change out? A pH of 7.8 in the tank compared to a ph of 7.2 out of the tap is very large swing. If you do large water changes you might want to consider letting the replacement water sit out overnight to gas out before adding it to the tank when you do your water change. You can also add something to treat for the nitrates while the replacement water is gassing out.

You can get a truer reading of what your pH, kH and gH are by filling a cup with dechlored tap water and letting it sit out for 24 hours before testing.

Bryan

 

[DaveAndLiz]

Just done a complete water test and have the following results:

pH 8.0
ammonia: 0
nitrite: 0
nitrate 20-30

I've also just noticed that several of my fish (Neons, Siamese fighter) have tiny white spots on them. I have previously had a case of white spot (about 6 months ago). I have just put some King British White Spot Control to treat it.

added: On two occasions over the past few months I have attempted to introduce balloon mollys to the tank. Each time I have added a group of three and none of them have survived more than a few weeks. Could this be a sign of poor water quality? Are Balloon Mollys particularly susceptible to water problems?

 

[An t-iasg]

Hi DaveandLiz,
You have received some excellent advice!

Essayons89 had a good suggestion about letting your tap water sit out before measuring the pH. Try this: take a pH reading right out of the tap, then let the water sit for 24 hours (called "aging") and measure again. The pH value of my tap water falls as it ages. Your water is rising, so I wonder if something in the tank is causing that to happen. Do you have any rocks in the tank? If you do, take them out, and put a little muratic acid on them. I think this acid can be found at a hardware store. If they fizz after application of the acid, that means that they may be leaching minerals into your water.

What kind of substrate do you have? You could try leaving a second glass of tap water out to age, and putting some of your substrate in it. After another 24 hours, test the pH again, and see if the substrate is making the pH rise.

About your molly question -- I have never kept mollies. But they like some salt in their water. If they don't have any salt, they appear to be prone to diseaes.

The white spot may be ich. Read this article, and if you suspect ich, I would recommend the heat treatment. Medicines are only effective in the free-swimming stage of the parasite's lifecycle.

http://www.aquariumadvice.com/showquestion.php?faq=2&fldAuto=32

 

[RoK]

Mollies require hard water and apparently also anywhere from slightly brackish up to saltwater rather than FW.
I've had swordtails and mollies, they all seemed to die quite fast (I kept them with no salt and in soft water) even though all my other fish are doing great. Therefore, my conclusion is mollies are not really FW fish.
I have 2 mollies left but am not getting any more unless I get some sea salt and their own tank so they can actually thrive.

 

[Essayons89]

Mollies are an enigma to me. They have been captive bred and raised for so long that you would think that over time it wouldn't matter whether or not they were kept in soft or hard freshwater or in brackish. I have mine in a tank with a pH of 7.2 and they are thriving. I do have an empty 40 gallon breeder that I've been thinking about turning into a brackish water molly tank.

Bryan

 

[DaveAndLiz]

I did a pH test of a glass of tap water which had been left standing for 24 hours and got a value of 8.0. Straight from the tap it is 7.2. Is it normal for the pH to increase like this?

 

[Devilishturtles]

Mollies are an enigma to me. They have been captive bred and raised for so long that you would think that over time it wouldn't matter whether or not they were kept in soft or hard freshwater or in brackish. I have mine in a tank with a pH of 7.2 and they are thriving. I do have an empty 40 gallon breeder that I've been thinking about turning into a brackish water molly tank.

Bryan

I agree here. Mollies can thrive just as much in FW as they can Brackish, IME. I've kept them in pure FW before, and they have been fine, and thrived.

 

[Essayons89]

I did a pH test of a glass of tap water which had been left standing for 24 hours and got a value of 8.0. Straight from the tap it is 7.2. Is it normal for the pH to increase like this?

Yes. The gasses (specifically co2) will dissipate when the tap water is left to sit out. This will cause the pH to rise and give you a true a reading of what your pH actually is. Since you have such a large difference between the pH right out of the tap and that in the tank you might want to let the replacement tap water gas out overnight before doing a water change to avoid shocking the fish.

Bryan

 

[RoK]

Well I guess I've just had some bad luck with them then. One of my mollies does seem to be quite happy, the other one is starting to lose weight much quicker than it used to. I try feeding it a little bit more than usual but it doesn't look that it's belly is getting any bigger, it seems like it's just pooping it out right away.