Abalone

Alfonsino

Anchovy

Barb is a midcentury nickname name that, like Deb and Sue, feels terminally dates now. But with the revival of Barbie, Barb may not be far behind.

Barb

Barramundi

Bass

Bloater

Bowfin

Bullhead

Shortening Francisco somehow makes it sound even cooler. Cisco is also the name of a digital security company.

Cisco

Carp

Catfish

Char

Clam

Cobia

Crab

Croaker

A Dorothy nickname name with a measure of nostalgic charm. Kids will associate it with the funny fish character voiced by Ellen DeGeneres in the Pixar animated instant classic Finding Nemo.

Dory

Cool, musical modern choice, especially as a middle name. 

Drum

Dolphin

Flounder

Geoduck

Goby

Haddock

Hake

Halibut

Herring

Hoki

Icefish

Krill

Lingcod

Lobster

Marlin

Molly is one of the original nickname names, ALWAYS ranking among the US Top 500 girl names since statistics began, in 1880. Molly peaked in 1991 only to rise just as high again in 2011, and though softening retains a good measure of popularity and charm.
 
What is Molly short for? Molly originated as a diminutive of Mary, spawning from medieval variations Malle and Molle. Molly has been used as a stand-alone pet form of Mary since the Middle Ages, and has been consistently popular as an independent name in the U.S. over the past several decades.
 Likable and down-to-earth, mild yet saucy, Molly has a distinctly Irish feel as well, with such Gaelic associations as 'Sweet Molly Malone' and the martyred reformers known as the Molly Maguires. In the Jewish culture, Molly Goldberg was an early television personality. 
 Other references include the Revolutionary War heroine Molly Pitcher and the Molly Bloom character in James Joyce's Ulysses, as well as characters in novels by Fielding, Hardy, George Eliot, Dickens and Thackeray. More recently, "Good Golly, Miss Molly" was a Little Richard hit and Molly Ringwald a celebrity bearer.
 Amanda Peet is the mother of a Molly, as are Monica Potter and Veronica Webb.

Molly

Mackerel

Mahi Mahi

Minnow

Monkfish

Mullet

Mulloway

Muskellunge

Narwhale

Octopus

Opah

Oyster

The field of nature names is constantly expanding to include all species of flowers and trees and animals and birds and even fish. In addition to its appeal for anglers, Pike recalls Zebulon Pike, the explorer who discovered and gave his name to Pike's Peak.
 While Pike also shares the friendly feel of names like Mike and Ike, the word pike can also be a noun or verb referring to a long sharp weapon used to do not-very-friendly things to people.

Pike

If used at all these days, it would be to honor artist Jackson, whose first name would be far preferable. 

Pollock

Pangasius

Perch

Pickerel

Piranha

Plaice

<a href="https://nameberry.com/list/329/nature-baby-names">nature names</a>are in, and even fish names like Pike and Salmon are open for consideration.

Salmon

Swam into style and quickly out again, on Chad's fish- er, coat-tails.

Shad

Sardine

Scallop

Seabass

Shark

Shrimp

Skate

Smelt

Snapper

Snook

Sole

Squid

Sturgeon

Sucker

Swai

Swordfish

Tarpon

Tilapia

Tilefish

Tuna

Walleye

Whale

Whitefish

Yellowtail

vintageluvs's list "Nautical Names - Le Fruits de Mer" of 79 great name ideas: Abalone - Yellowtail!

Nautical Names - Le Fruits de Mer