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-   -   Harlequin rasbora going dark (http://www.tropicalfishkeeping.com/cyprinids-atherinids/harlequin-rasbora-going-dark-52708/)

MukiTheFish 09-30-2010 02:32 PM

Harlequin rasbora going dark
 
I have 5 rasboras, 2 were redish when I got them, but one of them is turning really dark all over the body. The eyes are redder then those of the others and this fish seems to be the biggest and a tad of a bully.

I haven't found any info on rasboras turning really dark bordeaux over night so if anyone has any idea if this is something to worry about? A sigh on a disease or anything?

pH = 7,9 dGH is >14 dKH about 10 no Cl2, nh4 = 0 NO2 = 0 and NO3 <25mg/l

T = 25C

CaliforniaFishkeeper 09-30-2010 03:04 PM

Quote:

Originally Posted by MukiTheFish (Post 482743)
I have 5 rasboras, 2 were redish when I got them, but one of them is turning really dark all over the body. The eyes are redder then those of the others and this fish seems to be the biggest and a tad of a bully.

I haven't found any info on rasboras turning really dark bordeaux over night so if anyone has any idea if this is something to worry about? A sigh on a disease or anything?

pH = 7,9 dGH is >14 dKH about 10 no Cl2, nh4 = 0 NO2 = 0 and NO3 <25mg/l

T = 25C

That's really high PH for Harlequin Rasbora. They're a soft water SE Asian species.

MukiTheFish 09-30-2010 03:09 PM

After quite some research, turns out constant pH is better then constantly jumping from 6,5 to 8.
I also read numerous posts saying rasboras can thrive in pH up to 8. There's a big piece of driftwood in the tank which should help lowering it. So should that be the cause, know of any pH loweirng ways that will have a long term effect?

Would active carbon change the pH at all?

Byron 09-30-2010 07:24 PM

I would not recommend keeping rasbora in a pH of 8. Our profile suggests 7.5 as the upper limit, and it notes that even though the fish will manage at 7.5 it still prefers and will be less likely to develop problems in soft, acidic water. [General info; I'm not suggesting the pH is the cause of the darkening.]

Carbon has no effect on hardness or pH.

CaliforniaFishkeeper 10-01-2010 02:03 AM

My Harlequin Rasboras are more orange with a pinkish tinge as opposed to red as well.

MukiTheFish 10-03-2010 06:36 AM

Well, I decided to add another rasbora to my 5, and the bordeaux one seems more of a normal colour now and less aggresive.


The ph of 7.9 doesn't seem to bother them, or at least that's my explanation, because today i have 3 couples spawning eggs on the tiger plant. Didn't plan on that so I have no chance of saving the eggs, but I thought rasboras needed ph of 6.6 to even wanna do that. Oh well, I'll just take this as a sign of happy fish. Right?;-)

cheers

Byron 10-03-2010 06:28 PM

Some species of soft water fish will spawn in harder water, but usually the eggs will not hatch. I don't know if this occurs with rasbora or not, so it will be interesting to see.

MukiTheFish 11-14-2010 06:18 AM

I've been monitoring my pH for a few weeks, and it goes from 7,9 to 8,2. Yesterday and today the rasboras were spawning again, but I don't think any eggs will hatch. They seem to munch them right away.

I was wondering, if I added demineralised water in a ratio 1,5/20 every week on the regular water changes, would that be a good idea?

SO basically, if I change 20liters per week, and replace it with roughly 18,5liters of tap water and 1,5 liter of DI water, would it soften the water and lower the pH gradually enough to not cause stress?
Could I just keep doing that indefinitely, or should i stop at some point?

http://www.shrani.si/f/3/ML/4iCYATlT/dsc00154.jpg
The pic is really dark, sorry bout that. Can't get my hands on the other camera.

Does anyone recognise the plant in the left corner, that's got red under the leafs? It came with the wendtii, by accident I presume.

Cheers,
Muki

Byron 11-14-2010 01:30 PM

I can't see clear enough to identify that plant.

Diluting the tap water with water such as rainwater (if safe to collect in your area), distilled water, or RO water would lower the hardness and pH accordingly. The extent would depend upon how much you dilute the tap water. If you decide on this method, I would gradually increase the dilution each week for several weeks and this would slowly lower the hardness and corresponding pH. Over this period the tank will settle at a hardness and pH comparable to the water being added.

Byron.


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