Urgent - What is this??

[Victor]

I know in a lot of cichlids, black marks are signs of stress. It could be a lot of things such as water quality or tankmates

[Luke78]

pdoutaz,

Glad to hear it wasnt anything to do with ammonia.Did you run a test for nitrite/nitrate? Did you recently change foods or introduce live food? Are these guys spending alot of time near the heater during the day or night when they sleep? Do you have heater guard on? Sorry asking a lot of questions , but i think we can figure this issue out.

Water tests negative for ammonia - anyone have any idea what the cause is???

[pdoutaz]

Just re-ran all tests - current parameters are:
PH: 6.4-6.6
Ammonia - 0.0
Nitrite: 0.1-0.3
Nitrate: < 0.5
GH - 240
KH: 40

Does this indicate too much or too little CO2? What is the best/easiest way to bring the GH down?

Thanks again

[April]

when discus get dark spots or back half dark.its nerve damage.
very strange..other than that..no idea. hope you figure it out.

[pdoutaz]

Thanks April!
Other then water changes, is there a good way to manage the GH levels. GH was never ANYWHERE near that high prior to adding HO lighting and CO2 - so I must admit I'm somewhat stumped on this one...

[pdoutaz]

Confirmed my test kit was expired, so I bought a GH/KH test kit - Have new numbers
GH is about 200, dKH is about 4

Any suggestions on how to best manage the GH??

[Morainy]

Pdoutaz, could it be that you are measuring your gh in mg/l or ppm, rather than in degrees? With a reading as high as 240, it could be that you're measuring ppm, which would be much less than that in degrees. Do you have a test kit that asks you to count the number of drops you add until the solution changes colour, and then multiply by 20? I do. That number is ppm.

I don't have my Hagen test kit info handy, but I pulled this information by another poster off the Planted Tank forum, to give you an idea of the math:

"Let's say that you used 10 drops to reach the end color of light blue. For the GH test, you multiply the number of drops used to reach the end color by 20 instead of 10 like the KH test. In this example, this gives you 200 mg/L or 200 ppm. To convert to degrees, you again multiply by 0.056. So, 200 x 0.056 = 11.2 degrees. You can get degrees from ppm another way. Divide your ppm by 17.86 to get degrees."

If that's the case, your degrees of gh might be closer to the number of drops you added before you multiplied by 20 -- say, 12 or 14.

Just a thought. I'm not an expert. Good luck with your fish. I'd love to know the answer to your original question.

[pdoutaz]

Yes, mine is count drops, multiply by 20

[Morainy]

Okay, that's good then. I don't think that your gh is so terribly out of whack. Maybe a few degrees. I don't know what a Columbian Jewel Tetra is, but if it's
Hyphessobrycon bentosi, for example, then Seriously Fish says that the gh should be 2 to 10 degrees. You've got perhaps 12 or 14 degrees.

If your water is just a little too hard and you've been adding Equilibrium, you can just do a water change and not add Equilibrium (or not as much). Take out any shells or any substrate that was intended for a saltwater tank.

I didn't notice where you live, but if your water is naturally hard then you might want to soften it. I have heard that filtering it through peat can help, but I haven't tried this.

But unless the dark patches are the tetras' way of showing stress or unhappiness(which is possible), I don't think that gh is the problem.

How do your fish seem? Do they seem healthy?

Good luck. This is very interesting!

Yes, mine is count drops, multiply by 20

[pdoutaz]

Thanks to everyone for all the info / suggestions, it have all been very informative.

Issue appears to still be limited to only the 2 fish, and based on the input I've had from this and another forum, my conclusion is they are somehow stressed. Only cause I can think of is my 2 (relatively) new ghost knife fish may be showing aggresion after the lights go out