Key to freshwater fish families in New Zealand
Start at the top and work your way through the choices in the table below. In this key, we have relied on obvious external features and have tried to avoid using technical terms. There are a few features you might not be familiar with - look at the labelled photographs below or in the glossary for a definition.
Using the key
Make your first choice (scales or no scales) on the table below; if your fish has scales you go to Item 5 and then make another choice based on what is described there. If your fish has no scales, you move to Item 2 and so on, until you reach a family name. Click on that name to learn more. Families of introduced species are marked with an asterisk. Use the Fish Finder if you have a common name for the fish you want to see.
Key to the Families
| Item | Characteristic | Next |
|---|---|---|
| 1 | Scales absent or embedded | go to item 2 |
| Scales present | go to item 5 | |
| 2 | Seven gill openings on each side of head | Lamprey (Geotriidae) |
| One gill opening on each side of head | go to item 3 | |
| 3 | Fish long and thin (snake-shaped) | Eels (Anguillidae) |
| Fish not long and thin | go to item 4 | |
| 4 | Barbels present around mouth | Catfish (Ictaluridae)* |
| No barbels | Whitebait and mudfish (Galaxiidae) | |
| 5 | Fish flat and plate-shaped | Flounder (Pleuronectidae) |
| Fish not flattened | go to item 6 | |
| 6 | Tail rounded | go to item 7 |
| Tail not rounded | go to item 9 | |
| 7 | One dorsal fin | Live bearers (Poeciliidae)* |
| Two dorsal fins | go to item 8 | |
| Three dorsal fins | Estuarine triplefin (Tripterygiidae) | |
| 8 | Gap present between dorsal fins | Bullies (Eleotridae) |
| No gap present between dorsal fins | Dart Goby (Microdesmidae) | |
| 9 | Adipose fin present | go to item 10 |
| Adipose fin absent | go to item 11 | |
| 10 | Lateral line present | Trout and salmon (Salmonidae)* |
| Lateral line absent | Smelt (Retropinnidae) | |
| 11 | One dorsal fin | go to item 12 |
| More than one dorsal fin | go to item 13 | |
| 12 | Head slightly flattened with a dark band between the eyes | Torrentfish (Pinguipedidae) |
| Head not flattened | Carps (Cyprinidae)* | |
| 13 | First dorsal fin with 4 spines | Mullet (Mugilidae) |
| First dorsal fin with more than 4 spines | Perch (Percidae)* |
* indicates the the families of introduced species.