# Sharp Rocks



## kelownacichlids (Mar 3, 2009)

Hi All,
I am just in the process of setting up my 72gal tank for Mbuna. I have really nice looking rock on my property here with many varied colours in it that I would like to use for tank decoration but I am worried that it might be too sharp on the edges. Will fish hurt themselves on sharp edges? Wouldn't they live around sharp rocks in nature?


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## edouthirt (Jan 22, 2008)

Mbuna will be fine in reagrds to the sharp edges. But take a close look at the rocks and make sure there isn't an ovious metallic shinyness to them. I can't really tell from these pics, but it can be very dangerous to add rocks to a tank that will eventually leach metals into the water.

That would definitely be my bigger concern.


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## kelownacichlids (Mar 3, 2009)

I gave them the muriatic acid test and they did fizz a bit but none of the colour came off so I hoped they would be safe. There is no pyrite in them and I thought that iron etc didn't come out in higher ph water. I will mine my rocks from a little deeper in the wall and will scrub/pressure wash/acid wash them all.
Kim


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## PsYcHoTiC_MaDmAn (Dec 26, 2005)

aaargh. yet again.

sorry but this gets to me.

if it fizzes then it means theres calcium in the rock. nothing else.

your talking about putting it in a Mbuna tank, which is hard water, therefore calcium isn't a bad thing.


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## dwarfpike (Jan 22, 2008)

You can also sand the sharp edges if you are really worried about it.


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## kelownacichlids (Mar 3, 2009)

PsYcHoTiC_MaDmAn said:


> aaargh. yet again.
> 
> sorry but this gets to me.
> 
> ...


That's what I had read, that the calcium that is shown to be there by the acid is good. I had also read that if stains on the rock were removed by the acid they were probably iron oxide and might be soluble over time. These ones didn't vanish or lighten so I guess they are just colouring in the rock and will never be toxic. I was really only worried about the sharp edges.
Kim


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## kelownacichlids (Mar 3, 2009)

dwarfpike said:


> You can also sand the sharp edges if you are really worried about it.


Too many sharp edges to ever begin to remove them.
Kim


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## prov356 (Sep 20, 2006)

The rocks look fine to use. Most are. Here's a good article with more info Suitability of rocks


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## kelownacichlids (Mar 3, 2009)

Thanks prov356, I had read that. The only problem was he didn't cover sharp edges, my main concern with these rocks as they seemed to be suitable in all other ways.
Kim


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## Riceburner (Sep 3, 2008)

find an old CLEAN steel drum and roll the rocks?


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## prov356 (Sep 20, 2006)

kelownacichlids said:


> Thanks prov356, I had read that. The only problem was he didn't cover sharp edges, my main concern with these rocks as they seemed to be suitable in all other ways.
> Kim


I think injury from sharp edged rocks is pretty rare. If I had bubble eye goldfish, then I think I'd be 
careful, but otherwise, no. Most fish are pretty adept at moving in and around rocks without getting 
injured. I've read about the concern here on the forum, but I think it's been exaggerated a bit. I'd go 
ahead and use them without worry. Just my .02


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## edouthirt (Jan 22, 2008)

> I think injury from sharp edged rocks is pretty rare. If I had bubble eye goldfish, then I think I'd be
> careful, but otherwise, no. Most fish are pretty adept at moving in and around rocks without getting
> injured. I've read about the concern here on the forum, but I think it's been exaggerated a bit. I'd go
> ahead and use them without worry. Just my .02


I agree. Since you are setting up a mbuna tank, they are very precise swimmers for the most part and pretty durable too. In fact if you look at pictures or videos of Lake Malawi, the rocks are rather pointy have defined edges and ridges much of the time... not quite as defined as yours, but definitely not as smooth as river rock.

The only time I have been worried about sharp rocks was with fancy goldfish that aren't very good swimmers and are easily damaged.


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## kelownacichlids (Mar 3, 2009)

Thanks guys, that really makes me feel better about using them. I kind of thought that it wouldn't be a problem, they should encounter sharp rocks in nature, but I figured it was best to ask question and see what everybody said :dancing: 
Kim
I just siliconed my BG into the tank and hope to get it set up in the next couple of days


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