Help! Sick fish need assistance

[FreshwaterRook]

Ok I was checking out my Convict Cichlid tank today to find two of my Convict Cichlids are very ill. I recently did a water change and some filter maintenance. I have a Fluval canister filter, which I changed the carbon and also some filter pads. I just did a strip test and these are the results: GH 180, KH 240, pH 8.0, NO2 0, NO3 between 20 and 40. Water temp 80. The only other changes to this tank was buying a new thermometer however it has been up and running for about a month. Their diet consist of New Life Spectrum, Tetra flakes and Bloodworms.

Now the symptoms I'm seeing with both Cichlids is that their bodies are almost completely black as well as their eyes and their also just laying at the bottom of the tank. I have moved them to a tank hospital that I have set up, however I'm not sure what the problem is so I'm not sure what to do for them. Please help. Thanks.

 

[Proteus55]

Sorry about your fish problem. I too have had some baffling deaths after a water change. First off, it is my personal opinion that massive water changes of 50% or more or more harmful than helpful; others will disagree, but I have been doing this since the mid 1960s and water condition today is even more problematic in many locales. First, it is good to run your water for ten minutes to clear out any impurities that may be present. Also, use Prime to dechlorinate; I use a little more than recommended. Know your water source. If it is city, try to find out what kind of maintenance schedule they follow, as sometimes in the spring they flush out with higher levels of chlorine. Convicts are generally hardy and often impervious to even the most grievous conditins, so your situation is indeed grave. Did you use Prime or another dechlorinator? Generally, you should change only parts of filter media at a time so as to prevent mini-cycles. Hopefully, others will chime in but I would contact your water supplier straight away. It is likely that there are many other angry aquaists in the greater Chicago area if there indeed was a localized water issue.

 

[SandyCheeks]

+1 to what Proteus said.

We have problems here also since our town added a new big "water treatment" plant. It's like they can't get a grip on the levels and over compensate, one week the water has that nasty bacteria smell and the tanks have a little bacterial bloom, the next week the chlorine is so strong it makes about makes you pass out and the tank goes into a mini cycle. Wreaks havoc on the aquarium as well as the outside plants.

Is it possible your dechlorinator didn't work? Feel bad for your fish