FishProfiles.com Message Forums

What is live Rock?

Chris

Live rock is marine/salt tank rock that has come basically direct from the ocean and kept 'live' by being kept damp and away from temp extremes.
Where I work we have had in three different types....names for rock from different sources and quality. We have Fiji, Tonga branch and Kupang. Some rock comes with little beasties in it...good and bad ones. And has algae and that sort of stuff on it too.

unless you have a sw tank, they aren't for you. like what was stated, it comes with bacteria, and micro organisms. kinda like live sand.

Live rock isn't just for marine tanks anymore, either. Primarily, yes, but now freshwater marketing gurus have started using the live this and live that phrase to indicate that there is live bacteria/sludge on their products.
It's used in freshwater to jump start a healthy bed of beneficial bacteria. Not worth it in my opinion, i can grow my own bacteria

It's used in freshwater to jump start a healthy bed of beneficial bacteria

This wouldn't be the right kind of bacteria anyway. The live rock bacteria take nitrates and ammonia and turn it into nitrogen gas. Inside the rock and live sand it is a very low (effectively zero) oxygen environment, that is why the end product is devoid of oxygen.

Whereas the bacteria in fw tanks must have oxygen to do their work, and why the end product, nitrate, contains many molecules of oxygen.

Now, if you set up an oxygen-free zone in your fw tank, it is possible. I have seen a few sumps set up for just this purpose. But, this is tricky, while the fw bacteria are pretty easy to grow like fallout said.

So you're telling me that all the bacteria on the surface and most of the nooks that do have access to oxygen are useless?

No, the nitrifying and the denitrfying bacteria are different species. The live rock bacteria are not the same species as the freshwater bacteria for cycling the tank. And, they are going in the reverse directions in terms of the chemical reactions, so the bacteria that go to nitrogen wouldn't help you start a colony of bacteria that go to nitrates.

Saltwater liverock contains both types of bacteria for saltwter. On the external surface there are nitrifying bacteria to change ammonia to nitrates and in the crevices where water and air do not circulate there are some denitrifying bacteria. Along with the sand that effectively keeps at least my saltwater tank at zero nitrates.

Freshwater liverock should also have the capability for both types of bacteria but usually we try to avoid allowing denitrifying bacteria in our freshwater tanks. I'm not sure the entire reason but toxic gases seem to be a bigger problem as well as the chance for a pocket to get disturbed and released. Perhaps it's because in a saltwater tank we utilize all sorts of critters from microscopic to various pods to snails and inverts which keep the sand stirred up and the tank cleaned. While in freshwater when people see the FW equivalent of SW pods they freak out and try to find a way to kill them. Same with freshwater snails. While in most saltwater tanks the more life the better in freshwater we tend to only want what we add directly such as the fish or certain desireable shrimp and snails to survive. I'm quite happy to see various amphipods, snails, worms, and so on come out of my saltwater liverock. They are important to the ecosystem of my tank and maybe we should start looking into ways to use such a variety of life in our freshwater tanks.

Freshwater liverock should also have the capability for both types of bacteria but usually we try to avoid allowing denitrifying bacteria in our freshwater tanks.

Exactly.

Would freshwater rocks that have plants like Java ferns or moss anchored to them be considered "live rock"?

Nahh I was thinking the kind for Marine Tanks...

Chris