Mopani wood - good or bad??

I have Malaysian wood in a tank and didnt even bother boiling or soaking it and it was fine, also has a second hand piece of mopani I've never had a problem with. The real issue behind the mopani controversy is that there are different grades of it, some is lighter and lower quality meant for reptiles and birds while the higher quality is very dense and should be sold as aquarium grade mopani. All wood will grow a white fungus for anywhere from days to weeks then one day disappear when your tank balances itself out. The real risk is when people over react to the white fuzz and try to boil a once harmless fungus into a toxic residue on the wood. I had 4 types of fish eating the fungus off my driftwood and they are all doing fine, its normal, its safe, so don't boil it. To be safe since you already boiled it let it soak for a couple days and replace water frequently, people have bought mopani and boiled it because they saw the dried fuzz and again over reacted causing the fungus to be broken down resulting in dead fish when they put the wood in.

The Malaysian Driftwood is dark brown, almost reddish-brown, sometimes near black, and heavy. It sinks immediately. Tannins are not too bad; I just soak new pieces for a couple days in a pail. This wood is more chunky, it is excellent as fallen logs, tree stumps (placed vertically, some pieces are perfect), and it has a lot of tunnels which is super for catfish and loaches who have a riot in this. You can see it (sort of) in the photos of my tanks under "Aquariums" below my name on the left. I have a lot of it.

The Mopani I have never liked, but it does come in branch-like pieces which is useful. I get it mixed up with grapewood and Manzanita wood. Not sure if these are all different or not, stores often mis-label stuff. Some of this wood will carry fungus.

Now, there are many, perhaps hundreds, of species of fungus. Some is highly toxic, some is safe. Without knowing the species (and this means an examination by a microbiologist) it is impossible to say. But I have killed fish with a fungus that appeared on a piece of this wood, and I know others too. I will never again take the risk.

Byron.