Mermaid Short Stories

This is hardly a complete list, it's just the ones I happen to have to hand.

Sea Wrack by Marion Zimmer Bradley

The Merman by L. Sprague de Camp

Magritte's Secret Agent by Tanith Lee

The Mermaid by Tanith Lee

Because Our Skins Are Finer by Tanith Lee (selkies)

The Undine by Jane Yolen

The Corridors of the Sea by Jane Yolen

The River Maid by Jane Yolen

"The True Story of the Little Mermaid (as written by Hans Christian Anderson)", a zombie mermaid story by Michelle McCrary in Feary Tales

"The Mermaid's Child" by Abbie Farwell Brown, The Flower Princess

The Mermaid Hunter by Casey J. Prescott

Mermaid Fiction Online

Mermaid fiction podcasts

The Fiction of Deborah Smith

Miss Carstairs and the Merman by Delia Sherman
A 19th-century biologist catches a real merman.

A Journal of Certain Events of Scientific Interest from the First Survey Voyage of the Southern Waters by HMS Ocelot, As Observed by Professor Thaddeus Boswell, DPhil, MSc
-or-
A Lullaby

By Helen Keeble

How the Mermaid Lost Her Song
By Mark Teppo

The mermaid: a love tale by Lily Dougall

Elfleda
by Vonda N. McIntyre

Superluminal
by Vonda N. McIntyre

The Natural History & Extinction of the People of the Sea
by Vonda N. McIntyre

A Spy in Europa
by Alastair Reynolds

Emerald Sea
by John Ringo

The Mermaids Singing Each to Each
by Kat Rambo

The Green Leopard Plague by Walter Jon Williams

The Mermaids' Tea Party by Samantha Henderson

Something in the Mermaid Way by Carrie Laben
Be warned: not a pretty story!

Quartet, With Mermaids by Alan Smale