The annual flood pulses of central Amazonian rivers inundate marginal forests to 10 m depth or more (Furch & Otto 1987, Junk et al. 1989). The regularity of this flooding seems to have promoted the development of a complex relationship between forest plants and fishes that consume their seeds (Goulding 1980). Several fish species migrate into the flooded forests to feed on buoyant fruits and seeds, and many plant species reach their fruiting peak during the flood season. Fruits and seeds have been reported to have adaptive features related to water (hydrochory) and/or fish (ichthyochory) dispersal (Araújo-Lima & Goulding 1998, Gottsberger 1978, Goulding 1980, Kubitzki & Ziburski 1994, Scarano 1998, Williamson 1999, Williamson & Costa 2000). Strong multicuspidate teeth in frugivorous fishes, fruit/seed buoyancy (Goulding 1980) and chemical signs released by fallen fruit to attract fish (Araújo-Lima & Goulding 1998) are mechanisms for the seed dispersal of the flooded forest community.