A. Fungus may grow on driftwood immediately after starting to use it as it still contains residual organic matters which bacteria feed on. In this case, suction out the fungus as much as possible with a thin hose and add algae eater such as Caridina Japonica and Otocinclus to the aquarium. After driftwood is left sunken in the water, the wood will be free from organic matters and subsequent fungus infection.