Wood blocks inoculated with fungi were placed in a stream in order to investigate their interactions with the native mycota. Wood blocks were inoculated with single or paired isolates of tropical fungi, whereas no fungi were inoculated onto controls. After 3 months, the wood blocks were collected and the number of newly colonizing fungi were identified. More fungi were found on uninoculated than on wood blocks pre-inoculated with Chaetosphaeria sp. Neither Nais aquatica or Annulatascus velatisporus inhibited colonization when inoculated singly. However, in combination, they inhibited colonization by other fungi, indicating an interaction between the two species. Inoculated wood blocks were generally first colonized by hyphomycetes, with a low occurrence of ascomycetes. The study also showed that autoclaving wood for use in experiments affects the outcome of the experiments, i.e., affects the structure of the fungal community.