Start with high-confidence invertebrate biology books, then narrow by subgenre or adjacent topics.
Eels
James Prosek
The Book of Eels
Patrik Svensson
What a Fish Knows
Jonathan Balcombe
Every Last Fish
Rose George
A Field Guide to Coastal Fishes
Valerie A. Kells, Kent Carpenter
A Field Guide to Tropical Reef Fishes of the Indo-pacific
Gerald R. Allen, Roger Swainston
Valerie A. Kells, Luiz A. Rocha
Shark Biology and Conservation
Daniel C. Abel, R. Dean Grubbs
Crayfish, Crawfish, Crawdad
Zackary A. Graham
