Three new species of siphonophores (Rhodaliidae), a little known, uniquely benthic, family of Physonectae (Hydrozoa, Cnidaria), are described from specimens observed and collected at depths between 120 and 36o m off Indonesia and South Africa by the submersible JAGO. Special reference is made to in situ observations and video close-ups that revealed detailed information on locomotory, fishing and feeding behaviour.