Marine life identification sources online

Updated: 17 Apr, 2022

While a good library is handy, sometimes a particular species is difficult to identify. Fortunately, there are some great communities out there to help and encourage budding ecologists!

I will expand this page as more suggestions and recommendations come in, so if there is something you find useful that isn’t here, please let me know!


Note: please read the group rules before posting.

ID please – Marine Creature Identification

12,000+ members and open to a broad range of posts.

Marine Life Secrets

A new group to mix Photographers, Marine Biologists, Divers and Snorkelers. Not just for asking for ID, but also for sharing known ID’d species. Group is run by the Reef ID book authors.

Nudibase – Sharing Nudibranch Knowledge

Nudibranchs and all of their related sea slugs. No flat worms, please!

Lots of great nudibranch resources in the “Files” section as well.

Nudibranchs Australia ID Group

A citizen science research group dedicated to locating and identifying nudibranch species across Australia.

Nudibranchs Victoria

This group is dedicated to IDing and sharing images of nudibranchs specifically from and around Victoria, Australia.

Nudibranch Central

Avoid this group; the admin encourages the moving and manipulation of subjects. Also, rejects modern taxonomies which causes confusion in IDing species.

Marine Flatworms

For IDing flatworms.

Crustacean Identification Group

For crustaceans – shrimp, crabs, lobsters and so forth.

All Fish Species Identification

For fish, and is open to a wider range of images, such as from fresh water, or from fishing and hunting.

(Many sites and groups promote safe, non-contact interactions only, and as such ban any photo with manipulation, touching, or hunting.)

Frogfish Images

A group dedicated to photos of Frogfish.

Frogfish Lovers

Avoid this group; they encourage the harassment of marine life. Not run by a diver or photographer.

Cypraea – Cowry – Ciprea – Cowries – Cipree

Just for Cowries. Shells or the whole animal; both are allowed here.

Stromboidea Rafinesque, 1815 A Malacological Confederated Group

Photos and discourse related to stromboidea or strombidae (a group of large snails).

Marine Molluscs – Photos, Biology and Behavioral Ecology

For gastropods, bivalves and cephalopods. Living subjects only – no shells or exoskeletons.

Echidnoderms of the Indo-Pacific

For all things Echidnodermy! Sea stars, brittle stars, sea urchins, sea cucumbers, feather stars and basket stars and related radially orientated things.



My Reef Guide

A fantastic guide covering the Red Sea and Indo-Pacific areas. 1,857 different species so far. Fish, coral, and more.


This is a well regarded site with over 190,000 species of plants and animals recorded.

One of the world’s most popular nature apps, iNaturalist helps you identify the plants and animals around you. Get connected with a community of over 750,000 scientists and naturalists who can help you learn more about nature! What’s more, by recording and sharing your observations, you’ll create research quality data for scientists working to better understand and protect nature. iNaturalist is a joint initiative by the California Academy of Sciences and the National Geographic Society.

If you want to share your pictures, access a Life list, mapping, names dictionary and have other people checking your identifications on a worldwide scale then iNaturalist is a very good option. Validated records get transferred to Global Biodiversity Information Facility (GBIF). It also has a Seaslugs of the world project, with 31,000 records of 1,206 species (today).

There is a free app for Android and Apple devices as well!


While it was a great website, with a huge database, this site stopped being updated several years ago (circa 2018). There are a lot of small errors from either being out of date or from too small a sample/data size. I recommend using Fishes of Australia instead, if it is in that broad part of the world.

Project Noah

Project Noah is an award-winning software platform designed to help people reconnect with the natural world. Started at NYU’s Interactive Telecommunications Program in 2010, the project began as an experiment to mobilize citizen scientists. Backed by National Geographic, Project Noah is mobilizing a new generation of nature explorers

There is a free app for both Android and Apple devices for Project Noah.


French-language based.

DORIS has records of marine species of animals and plants, entirely realized by volunteer amateurs and scientists, within the framework of the French Federation of diving ( FFESSM ) and its commission of biology ( CNEBS ).

Australia (and surrounds)

Fishes of Australia

This is one of the primary ID sources for fish around Australia. A fantastic range of fish. Hosted by Museums Victoria. Often an extensive collection of common names included, making it easier to find some fish.

Atlas of Living Australia

This website covers both marine and terrestrial animals, and is a thorough database.

Australian Museum

This is a broad site, with a lot of resources. Unfortunately, a small selection of ID pages (1,175 ‘fact sheets’), but the image quality is good.

Great Barrier Reef

Eye on the Reef

If you submit photos to the Great Barrier Reef Marine Park database, not only does it get identified for you but the observation is lodged as a data record under your name!

Western Australia

My Critter Compendium

A growing page of fish specifically around Perth, but most can be found very wide ranging up and down the coast; many as far north as South East Asia (Indonesia and Philippines).

Fishes of Mettam’s Pool [24.3MB PDF]

An A3 poster curated by a local biologist and his children, this is a fantastic collection of fish that have been found at one small site in northern Perth. Only common names are included, so to get more information, please use Fishes of Australia. Check out his artwork too!

Nudibranchs / sea slugs / etc

Seaslugs of the World (at

Contains 1,206 species of sea slugs (nudibranchs, etc.).

Nudibranch Central

Australian-based, but world-wide. Supports their iPhone and Android ID apps as well.

Mediterranean Slug Site

German-English. For Mediterranean slugs.

OPK Opistobranquis

Spanish / Catalan / English. For Mediterranean and Iberian molluscs.

Seaslug World

Japanese-language based, with 1,533 species.

Seaslug Forum

An extensive resource for all things relating to sea slugs.

However, there have been many changes since the site stopped being updated. As such, we can’t really use the Sea Slug Forum for IDs anymore.

It is a great starting point and an invaluable resource, but it is many years out of date.

It is good if you want to compare to the photos that are on it.

Shelled molluscs

Worldwide Seashells Collection

A huge collection of images. Snails, chitons, tube worms and even cephalopods. If it has a shell, they’ll have a record of it here.


Fish Database

The database contains 8327 pictures of 1559 different species of fish.


Ryan’s Website

A decent collection of photographs of ID’d crustaceans. Be aware that the website is very basic and can be difficult to use, and is not web/mobile optimised at all (very data heavy).


If you’re going “off-grid” (away from the internet) and taking books with you is too much hassle, then consider taking some digital books with you, on your phone, tablet or kindle.

There aren’t a lot of big publisher options out there, but there are a few. (Note: For color Kindle books, I recommend the Kindle Fire)

Some books are even free!

Cardinal fish

Written by the very famous (widely published) Rudie Kuiter, this expansive book on Apogonidae fish (cardinal fish) is free to download from (40MB PDF).


Teresa (Zubi) Zuberbühler wrote a brilliant book on specifically frogfish. It’s available as a PDF.


Western Australian Department of Fisheries

Recreational fishing identification guide

The Department of Fisheries has a free book of common marine life: fish, sharks and crustaceans. While aimed at fishermen, it just as useful to divers. Direct link to PDF.

Resource sheets and Fact sheets

To gain a better understanding of the biology of marine life, and how to identify them, the DoF has released a series of one-page Resource sheets (on the right side of this page) for “beachcombers”.

This covers chordata, mollusca, cnidaria, echinodermata, porifera, annelida, bryozoa, crustacea, seagrasses and algae.

For more in-depth information on marine life, the WA DoF has published a series of 3-4 page PDF pamphlets about a number of species in Western Australia. For example, on whale sharks.

WA DoF links

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