[Gareth dePutron]

I've had a 70 gallon cichlid tank for about 5 years. Occasionally I've lost fish do to my time constraints. Now that I'm retired, I can more closely monitor conditions. Until last week, everything was perfect. I added three fish (usually I add one at a time). Possibly overfed the first night. Nitrate levels went red, and Nitrite went up. Ph went down. Ammonia was zero. I've changed out probably 50% of the water and made sure the filter was clean. In the past two days, I've lost my big Jewel and both Pictus Cats. The cats stayed near the surface, while the Jewel remained at the bottom. After removing the Jewel, I noticed a slight slime coating. The newer fish are acting normally, but the other four are lethargic and hanging close to the surface in a corner. All but the Neon Blue seem to be eating just fine. The only other fish is a 12-year-old Plecostimus. Now signs of aggression such as fin damage (the Jewel was the only aggressor). Water temperature is a constant mid-70s. I have tried to raise the pH using limestone and ATI pH Up, with minimal results. Same with a detoxifier. I hesitate to add more of the chemicals, as I have already done the maximum according to the instructions. Current levels: High pH - 7.6; Nitrite - 0.25ppm; Nitrate - 10.0; Ammonia - 0.0. All of the cichlids are Malawi. I've had three for 9 months, the rest are more recent. I'd really like to save what I have left. Suggestions? More info needed?

 

[Deeda]

Welcome to C-F!!

Sorry for your recent fish losses.

Can you test your tap water pH, nitrite and nitrate levels just for a base point? Are you using treated city water or untreated private well or cistern as your water supply?

It is very possible that your filtration wasn't able to handle the additional fish load OR you cleaned the filter too thoroughly OR you hadn't been keeping up on your regular water changes. These are all common occurrences so it can be difficult to pinpoint the problem.

Assuming your tap water pH is between 7.2 and 7.8, there is no reason to try and adjust the pH.

Which type and brand of test kit are you using and how old is it? An old kit will give you false readings, either low or high.

Once you post your tap water results and they are within the pH range above and there is no ammonia, nitrite & nitrate present in it, doing 50% water changes should not be an issue. However, it it's been awhile since you have done regular water changes, that can be an issue that is called 'old tank syndrome' and may be why you lost some fish.

What are the dimensions of your tank?

What brand and type filters are you using? It's possible the filter cleaning impacted the good bacteria level in the tank which is why you are experiencing a nitrite spike.

 

[Gareth dePutron]

Thanks for the reply. Tap water baselines: pH 7.7, Nitrate 0.0, Nitrite 0.10, Ammonia 0.0. I use an API test kit (less than a year old). Filter system is Fluval 306. I usually clean the filter once every two weeks, with a 25% water change. Perhaps I am cleaning the filter too thoroughly. Right now, the only fish not eating is my Neon Blue. Tank dimensions are 48"Lx12"Wx24"H. I have been using a powerhead to airate in addition to the big filter.

 

[Deeda]

Thanks for the info.

Odd that you have a nitrite reading in your tap water. Just for a comparison, test some bottled water and see if the results change. It's possible the test tube has some residue from a previous test or you were a bit off when you did the testing. You should be able to get a water report from your water provider online to double check most parameters though that is done at their water facility.

As to the pH of the tap water, you can also leave a sample out in a clean glass container for 24 hours and test the pH again to see if it changes. If it remains close to your baseline, no reason to add product to change it. I'm guessing you saw a spike due to either insufficient water changes, dirty filter or higher than normal bio-load.

What water conditioner are you using? If using Seachem Prime, follow the instructions for dosing for a high nitrite concern.

Most people clean their filters too little but every 2 weeks seems frequent. Do you see much gunk in the filter when you clean it?

 

[Gareth dePutron]

Moderate crud in the filter at two weeks. Heavier if there's been an over feed. I'll try a filter cleaning at three weeks. I monitor the fish behavior and can usually tell if something is off. Thanks for all your help.

 

[Deeda]

You may want to try and feed a bit less since that is probably getting into the filter. I know it's difficult to judge how much to feed because they always look so hungry!

What brand, type and size food are you feeding?