Unnamed fish

The following is a list of unnamed fish.

Archer IV fish

Some eel-like fish were seen swimming in a lake on Archer IV. (ENT: "Strange New World")

In the script for "Strange New World", these animals were described as "spikey, eel-like alien fish."

Ba'ku fish

A blue fish was seen swimming past Data in the Ba'ku lake. (Star Trek: Insurrection)

Cardassian fish

Promenade fish 2 — A Cardassian fish skeleton on the Promenade

The skeleton of a huge Cardassian fish was displayed on Deep Space 9's promenade. (DS9: "The Nagus")

The official book The Making of Star Trek: Deep Space Nine features a sketch of the giant fish. Here, it is mentioned that that fish is supposed to be a "Cardassian Sushi Ad" and that "it is known simply as the Fish".

Cetacean Institute fish

Several different species of fish were seen in large aquariums in the Cetacean Institute in Sausalito. (Star Trek IV: The Voyage Home)

Enterprise-D aquarium fish

Fish Picards quarters — An aquarium in Picard's quarters

Captain Jean-Luc Picard's quarters aboard the USS Enterprise-D contained an aquarium full of colorful tropical fish. (TNG: "The Battle") Similar aquariums were also present in the guest quarters of Doctor Paul Stubbs, (TNG: "Evolution") and the quarters of Counselor Deanna Troi. (TNG: "The Survivors")

Hima fish

A species of small fish swam in the lakes of the planet Hima. The fish had blue-and-black or orange-and-black stripes, with four appendages extending from the rear of the animal matching the blue or orange stripes. In 3188, a school of these fish were spooked when Cleveland Booker and Michael Burnham were transported into the water. (DIS: "That Hope Is You, Part 1")

K'Tuevon Prime eel

A tank full of eels was present at Imperium Magistrate Clar's history stone etching party on K'Tuevon Prime in 2380. Guests who displeased him were put into the tank, which was known as the Tank of Contempt. (LD: "Veritas")

Qualor II fish

The Ferengi Omag had a very large fish for dinner in a bar on the planet Qualor II. (TNG: "Unification I")

Trill fish

A species of flying fish swam in the ponds of the planet Trill. The fish had orange skin. In 3189, several of these fish were swimming in and flying over a pond near the Caves of Mak'ala when Michael Burnham and Adira Tal visited the planet. (DIS: "Forget Me Not")

The Waters marine life

Seamonster attacks the Delta Flyer in The Waters — A massive eel-like aquatic creature attacks the *Delta Flyer* at the center of The Waters.

This marine lifeform was encountered under the surface of "The Waters" at a depth near 600 kilometers. The creature, which was likened to the electric eel found on Earth, was significantly larger and more powerful that the Earth counterpart, as it emitted biothermic discharges that exceeded 500,000 volts. (VOY: "Thirty Days")

Xyrillian fish

A large tank on the Xyrillian starship had eel-like creatures swimming in a liquid within it. (ENT: "Unexpected")

It is unknown what function these fish serve or what liquid they are swimming in. It can not be water, as it is revealed in the episode that the Xyrillians have trouble producing water. Indeed, the closest approximation they could devise was a small gelatinous cube.