If you were the kind of kid who felt really, really sorry for the goldfish swimming in circles in that tiny, boring bowl, “What a Fish Knows: The Inner Lives of Our Underwater Cousins” is the book for you.

Author Jonathan Balcombe, director of animal sentience at the Humane Society Institute for Science and Policy, says most people see fish the way poet D.H. Lawrence did: “Soundless, and out of contact. . . . Not one touch. Many suspended together, forever apart.” But new research is constantly illuminating how fish experience the world, he says, and he argues that they have personalities and relationships. This book is his attempt to “give voice to fish in a way that hasn’t been possible in the past.”

There’s science here (for example, a discussion of electro­reception, the ability of more than 300 species of fish to perceive and interact with the electrical signals generated by other fishes’ nerve endings), but the book leans a little toward anecdotal observations and hopeful interpretation.

Balcombe repeats stories from people who observed fish behaving with personality: Divers befriend a Bahamian grouper that repeatedly swims alongside them and rolls over like a puppy to be “properly petted.” A man catches hold of a bright orange Midas cichlid and playfully tosses it back into the sea — and the bright orange fish, resembling a “character from ‘Finding Nemo’,” swims back to be tossed again and again. An economics professor reports that the Oscar cichlid in his aquarium always spends the night on the side of the tank that’s closest to his bed; when he rearranges the furniture, the fish switches sides. “Is it friendship?” Balcombe wonders. “Maybe, maybe not.”

And Siamese fighting fish, released from the “artificiality of captivity,” stop killing one another, he writes, and instead exhibit cooperative group behavior, with lesser males deferring to stronger ones.

Balcombe wants his readers to think about the hundreds of billions of fish that humans kill each year (the exact number is impossible to determine), and he points out that the catch is usually described in the impersonal “tons” rather than in numbers of individual living creatures. To make his point, he never uses the word “fish” as a collective plural, the way most of us do — if there’s more than one, they are “fishes.”

As research continues, fish may earn a little more human respect. “In parts of Europe,” he writes, “it is now unlawful to keep a goldfish — a naturally social animal who can live for decades — alone in a barren fishbowl.” Sensitive kids would approve.