“Of course they don't function as gills, but five-week human embryos can be regarded as little pink fishes, with gills.”

“Writers fish for the right words like fishermen fish for, um, whatever those aquatic creatures with fins and gills are called. 
”

“the mangrove killfish, lives in South American and southern US coastal swamps that can either dry up or become so toxic that the fish has to find refuge in the mud or by flipping and jumping across land. Amazingly, its skin and gills change so the killfish can breathe air and survive out of the water for as long as ten weeks.”

“Human?' The girl cocked her head the other way. I caught a glimpse of pink gills under her chin. 'My sisters told me stories of humans. They said they sometimes sing to them to lure them underwater.' She grinned, showing off her sharp needle-teeth. 'I've been practicing. Want to hear?”

“I’ve seen fish hooked who keep more patience in their worst gill than some of you have in your best moods. If you were a sandwich at McDonalds, they’d call you the McGrump.”

“Or. I hate that word. It’s two letters long and stuffed to the gills with reasonable doubt.”