Lava rock: good or bad

[coldmachineUK]

I have read conflicting articles about the use of lava rock in aquaria. They're so conflicting, that the extremes are:

1. Lava rock contains anaerobic patches which will build up toxic bacteria such as botulism, which will kill your fish;

2. Lava rock is porous and is therefore able to develop beneficial bacteria and can actually assist in the filtration of water within your tank, particularly for denitrifying: some people even use lava rock for pond filtration.

So, what do people think? Is this another Myth? I'm going to write in to PFK magazine about this to 'ask the experts' too, and will reply here with their response (if I get one!).

 

[neilanh]

What's your goal in considering the lava rock? If it's to address item 2 that you stated, ceramic rings are extremely porous and allow for the buildup of the beneficial bacteria, and are known to be safe, and great for your tank.

If this is your goal, I'd go with the ceramic rings. Others on here may have experience with lava rock that can answer, though.

 

[SparKy697]

I thought this was an interesting article. An interesting site as well.

 

[JDogg]

I have read conflicting articles about the use of lava rock in aquaria. They're so conflicting, that the extremes are:

1. Lava rock contains anaerobic patches which will build up toxic bacteria such as botulism, which will kill your fish;

i have never heard of this happening, but it also seams theoretically possible to me.

i know the anaerobic spots exist, they are in fact counted upon when lava rock is used as base rock to be turned to live rock in a SW tank. how those pockets affect FW i do not know. but i do know many use lava rock in there FW tanks and i have never heard of these anaerobic pockets being linked to fish death.

 

[coldmachineUK]

Thanks for the replies so far everyone
I use lava rock in my cichlid tank for decor (and territory). It's packed quite high, there's a lot of the stuff, and it's been in there 5 months, coming up to 6.

If it had 'turned anaerobic', would it have happened by now and would my fish have already died by now?

I found this article: it seems to really dismiss the theory that lava rock builds up anaerobic bacteria (like botulism): http://www.exit109.com/~gosta/pondaner.htm

But, as I say I keep finding totally contradictory stuff. Also that article relates to the use of lava rock for pond filtration: not exactly the same as my reasons for using it!

 

[Zagz]

I have 30 lbs of lava rock in my tank and I do move and restack it every couple of water changes to make sure that I clean inbetween it. The detrimis seems to really build up in there. I don't have any problems with it at all. My cichlids love to hide in it all the time. A lfs here also has a 500gal cichlid tank with probably a hundred lbs lava rock and they never move it at all.

 

[neilanh]

I guess I totally missed that you wanted to use these as decor - don't know what I was thinking. Ceramic rings might look a little silly in there huh?

Sorry bout that...

 

[Sicklid]

You have already seen this one, CMUK, but I figured I would post this just so others can respond and prove me wrong or right.

The only way anaerobic pockets could be dangerous is if they release into the water column. I'm no scientist, but I would imagine that

1: the pores of lava rock are somewhat "closed cell" and only let water in a bit deeper than the surface, and

2: unless you crack one open like an egg, that the anaerobic pocket could never see the light of day and will be safely sealed away inside the center of the rock.

While I think it is not quite a myth and it could very well happen theoretically, I doubt you would have a problem. Here's another example of a tank full of red lava:

http://www.malawicichlidhomepage.com/aquainfo/hobbyist_gallery/hobbyist_steinhaus.html