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 hope to slowly expand this page as more suggestions and recommendations come in.
12,000+ members and open to a broad range of posts.
Nudibranchs and all of their related sea slugs. No flat worms, please!
Lots of great nudibranch resources in the “Files” section as well.
For IDing flatworms.
Just for Cowries. Shells or the whole animal; both are allowed here.
Photos and discourse related to stromboidea or strombidae (a group of large snails).
For gastropods, bivalves and cephalopods.
An extensive resource for all things relating to sea slugs.
The database contains 8327 pictures of 1559 different species of fish.
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.
Some books are even free!
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.
This covers chordata, mollusca, cnidaria, echinodermata, porifera, annelida, bryozoa, crustacea, seagrasses and algae.