An annotated checklist for indigenous fishes recorded from Hong Kong streams and rivers is provided by Chong and Dudgeon (1992). The freshwater fish fauna of Hong Kong varies enormously and there are around 100 recorded indigenous species. Thirty five of these species are marine vagrants, but the remainder are true freshwater fishes (AFCD Homepage, http://www.info.gov.hk/ afd/conserv/fauna.htm, downloaded December 1999). Gobies dominate the river and stream fishes, comprising 16 genera and 21 species. Ten indigenous fishes in Hong Kong are threatened with extinction or may be locally extinct already (Chong and Dudgeon 1992). All are either primarily freshwater or amphidromous (ie capable of living in saline waters) species which seem to be confined to lowland rivers and streams. The reasons for their decline are not clear but habitat alteration (eg channelisation) and pollution are likely to be causative factors. Fish species such as the Minnow (Aphyocypris lini) are endemic to Hong Kong but reported to be under threat. Others such as the Black Paradise Fish (Macropodus concolor) have a very limited range, occurring locally in only 5 locations (Chan 1999), with a single population outside Hong Kong being reported in northern Vietnam ('About Life' 1999). New species have been added continuously to the fish species database of Hong Kong. For example, the Ayu (Plecoglossus altivelis), a small migratory salmonid, has been discovered in streams at Tai Ho on Lantau Island.

Terrestrial invertebrates are mainly composed of insects (eg butterflies, dragonflies, damselflies, bugs), arachnids (eg spiders, scorpions), myriapods (eg centipedes, millipedes) and annelids (eg earthworms, leeches). While some species are confined to stream habitats (eg leeches, dragonfly nymph), others can be seen in almost any vegetation habitats (eg butterflies, dragonflies). Other insects such as grasshoppers and wasps are commonly observed in forest, shrubland and grassland areas.

Both butterflies and dragonflies exhibit high diversity in Hong Kong with about 225 species of butterflies having been recorded (Walthew 1997) and 100 species of dragonflies (including damselflies) being recorded (AFCD Homepage, http://www.info.gov.hk/ afd/conser/fauna.htm, downloaded December 1999). Annotated checklists for both butterflies (Walthew 1996) and dragonflies (Wilson 1995 and 1998) have been published in recent years.