Hi all,
Out of curiosity, if I did put it in the tank with the softer wood on there, what would happen?
Really depends on how much oxygen is the tank water.
The reason for this is that the wood is soft because the "structural carbohydrates" that give wood it's strength (cellulose, hemi-cellulose and lignin) are being degraded, and the smaller carbohydrates they contain then become available. In the same way as the starch in a potato is comprised of lots of glucose (a mono-saccharide sugar) locked together, so are cellulose and lignins - "long strings of glucose very tightly chemically locked together".
Mainly only "white-rotting" fungi can degrade lignins, but all organisms can use glucose they unlock, so the soft wood will lead to a build up of bacteria and other types of fungi feeding on the wood. Wood is very deficient in nitrogen, but the ammonia from the fish will supply this leading to a microbial "bloom and bust" cycle.
Decomposition has a high oxygen demand (measured as the BOD - Biochemical Oxygen Demand), and this may exceed the oxygen being exchanged leading to de-oxygenated water and fish death, the decomposition processes will also produce CO2 which may inhibit oxygen take up by the blood due to the Bohr effect.
So don't put soft wood in your tank. The only circumstances where it would be a good idea is if you keep Panaques and feed it to them in limited amounts. This was found by some research by Dr Donovan German, who found that despite their obvious adaptations to wood feeding Panaques don't have the gut flora to actually digest intact wood (like Termites do), but rely on eating semi-degraded wood (search through the back threads for more details).
An analogous situation would be Leaf cutter ants, where they chew the cut leaves up, but feed the chewed material to their fungal colony, and eat the fungus after it has degraded the cellulose to sugars.
cheers Darrel
