The Poor Knights Islands in New Zealand are a hotspot for marine biodiversity, and that includes a spectacular variety of nudibranchs—some of the most colorful and fascinating sea slugs in the world. Thanks to the warm East Auckland Current, subtropical species mix with temperate ones, creating incredible diversity.
Below is a growing list of some of the amazing ones we have seen and photographed since 2012. This page will be added to as we find time to work on it and lucky enough to spot and photograph more species.
Spring is certainly the most exciting time for nudibranch hunting at the Poor Knights as many of the lesser seen species tend to be spotted from September through to November.
Aphelodoris lucuosa
Up to 75mm
Feeds on sponges
Cadlina flavomaculata
Yellow Spotted Cadlina but with dark gills
This beauty was seen at 30 metres at Middle Arch in 2024 whilst I was shooting wide angle.
In 2025 again shooting 16/35 around 30 metres at Fraggle Rock, I find another one.
80mm
Cadlina willani
Caldukia rubiginosa
Up to 15mm
Feeds on Bryosoans
Ceratosoma amenum
Clown Nudibranch
Up to 60mm
Feeds on sponges
Probably the most common and easy to see nudibranchs at the Poor Knights all year round. Commonly found near grey sponges.
Chromodoris aureomarginata
Up to 30mm
Feeds on sponges
Most commonly seen at night, but can be found during the daytime
Crimora multidigitalis
8mm
Feeds on Bryzoans
Coryphellina albomarginata
6-12mm
Feeds on Tubularia and other hydroids
Dendrodoris citrina
Uo to 65mm
Feeds on sponges
Found at night at Magic Wall in October 2025
Dendrodoris denisoni
Gem Nudibranch
Up to 80mm
Feeds on sponges
Easily seen all year
Diaphorodoris sp
10mm
Feeds on Bryozoans
Rare in New Zealand
Favorinus tsuruganus
Seen at Landing Bay Pinnacle in November 2023 at 30 metres.
Originally described from Japan and found uncommonly in eastern Australia down to about Sydney. Also been recorded in New Caledonia so it probably a wide western Pacific distribution.
Galeojanolus Ioannae
10mm
Feeds on Bryozoans
Janolus eximius
Up to 12mm
Eats bryozoans.
Found during the day at Maomao Arch on the eastern side in 2024 and at night on Magic Wall in October 2025.
Janolus ignis
Up to 60mm
Feeds on Bryozoans
Nocturnal, rarely seen during the day
Janolus mokohinau
25mm
Feeds on Bryozoans
Found in the Labrid channel 2023
Jason mirabilis
Upto 65mm
Feeds on Solanderia hydroid
Okenia atkinsonorum
12mm
Feeds on Bryozoans
Look on anything pink for these cute little guys
Roboastra luteolineata
Up to 125mm
Feeds on Tamja Verconis nudibranch
Tamja morosa
Up to 120mm
Feeds on Bugula dentata bryozoan
Tambja pulcherrima
Up to 75mm
Feeds on Bugula denetata Bryozoans
Uncommon
Tambja tenuilineata
Upto 50mm
Feeds on Bryozoans
Varies in shades on green
Most likely the second most common nudibranch at the Poor Knights.
Varying in shades of green, from a light almost yellow with light yellow stripes, to dark green with dark stripes.
Tambja verconis
Upto 100mm
Feeds on Bugula dentata bryozoan
This Tamja verconis and Tamja tenuilineata seem to be a having some cross species action.
Trapania rudmani
8mm
Feeds on Kamtozoans
Tularia bractea
10mm
Feeds on Athecate hydroids
To be ID’d
To be ID
Night dive Magic Wall October 2025
To be ID
Night diving Magic Wall October
To be ID
Sea Slugs
Sacoglossans – Sap suckimng slugs
Elysia species
20mm
To be ID
Night dive Magic Wall October
Slug
Whangarei Harbour
