# Seachem Onyx Sand bad for Corys



## awrieger (May 12, 2005)

Just as a warning for any potential purchasers of Onyx Sand who have barbelled fish. All my Sterbae Corries have lost their whiskers on this hard, sharp substrate.


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## aquamoon (Jul 26, 2004)

Thank you ......im setting up a 20 gal for my S. corries. ...i had some Onyx Sand not in use that i though they would love .......thanks


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## oceanaqua (Nov 24, 2005)

With such a hard substrate, you are bound to have scratches on your tank from the floating particles when you do an algae wipe down. Becareful. I have plenty of scratches now, thanks to flourite.


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## Rex Grigg (Dec 10, 2002)

Personally I prefer hard substrates. Much nicer than having mush in the bottom of the tank.


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## DiabloCanine (Aug 26, 2005)

awrieger said:


> Just as a warning for any potential purchasers of Onyx Sand who have barbelled fish. All my Sterbae Corries have lost their whiskers on this hard, sharp substrate.


I think you should look for another reason, I only use Onyx sand and have dozens of different cories, no problems here....DC


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## awrieger (May 12, 2005)

I really don't know what else it could be. Apart from the Onyx Sand, there's only soft sandstone rocks in there. The Onyx by contrast looks like sharp little gray gravel chips you might see in a quarry.

Unless it was the hairgrass... but I wouldn't imagine it would be abrasive or sharp enough though.

It didn't happen straight away. Took about 4-5 months for their barbels to slowly disappear to the point where they're now just stumps.


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## Rex Grigg (Dec 10, 2002)

Bacterial infections can cause that.


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## awrieger (May 12, 2005)

I didn't know that, thanks Rex. They look otherwise healthy and fine. So I may have been wrongly blaming the Onyx all this time then instead of dealing with the problem and nipping it in the bud...

Off to the fish disease book I go...


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## DiabloCanine (Aug 26, 2005)

awrieger said:


> I didn't know that, thanks Rex. They look otherwise healthy and fine. So I may have been wrongly blaming the Onyx all this time then instead of dealing with the problem and nipping it in the bud...
> 
> Off to the fish disease book I go...


Cory barbells will wither away if nasties reside in the substrate. Vac your gravel.....DC


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## awrieger (May 12, 2005)

DiabloCanine said:


> Cory barbells will wither away if nasties reside in the substrate. Vac your gravel.....DC


I've never vacced the substrate in the Ecocomplete tanks, and those Corys there are fine. And they've been there longer and still have lovely long barbels. It's just the ones in the Onyx tank.

PS. I suppose you could call it gravel. Onyx does indeed look like the stuff they mix into concrete. I don't like it much at all.


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## csf (Jul 10, 2003)

I've got flourite and have never had trouble w/ cory barbels. I heard where high nitrogen would also have a negative impact on their barbel lengths. 

I've got another tank w/ onyx sand, but no cories in there to test the theory.


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