Ginger (18, female) is a Clownfish Piscomaria with vibrant orange scales and drooping fins, and the protagonist of this work. She is cheerful, kind, and loves hugs, excelling at painting and underwater stunts. She lost sight in her left eye while protecting her friend Agnar and suffers from trauma where she bleeds from that eye when she cries, but this is also the source of her strength to protect others. She is resistant to anemone venom but sensitive to light. Though she sometimes gets confused by overthinking, she is a reliable presence who always supports her friends' hearts.

Azul (18, female) is a Betta Piscomaria with vivid deep blue and purple scales and smooth fins. A perfectionist who loves pearls and suits, she is kind, independent, and very popular at the university. She has the trait of glowing under UV light. Obsessed with beauty and cleanliness, she cares for her scales three times a day and enjoys handicrafts with Ginger (her best friend, whom she calls 'Az'). While she is troubled by the mischievous Neon, she has the kindness to forgive him, though she struggles with her relationship with her brother Lucian, who looks down on other species.

Aura (18, female) is a Goldfish Piscomaria with shimmering golden scales and the mysterious youngest member of the group. Since she cannot speak, she communicates through sign language and gestures. To hide her face, she always wears a special waterproof box with a mesh screen over the eyes and hates having it removed. She is bright and a bit of a joker who loves to sleep, but is super energetic once awake. She loves having her head patted and eating pancakes, and is a beloved character who sometimes acts like a needy attention-seeker.

Bubbles (18, female) is an anthropomorphic Dolphin (classified as fish-type) with lavender skin and heart-shaped pupils. She is cheerful, a huge glutton, and loves candy. She has a crush on Alex and often hangs out in his lab, but he is too absorbed in his work to notice. Due to the effects of swimming in contaminated water in the past, she suffers from periodic lethargy and fevers, but she is usually very energetic and excels at swimming and jumping. She is sensitive to sound and can hear ultrasound, making her a very high-energy girl.

Agnar (19, male) is a Shark Piscomaria with dark blue scales and sharp fangs. Due to the trauma of being caught by sailors in the past, he has unbreakable chains tangled around his neck and waist and is terrified of ships. He is powerful and soft-spoken but overprotectively cares for his companions. He deeply loves Ginger, who saved his life, and still regrets her loss of sight. He has a sharp sense of smell and is sensitive to noise. He has a charming side that can be bribed with his favorite fried chicken, and he enjoys playing games with Neon or surfing with Jelly riding on his tail.

Silver (18, male) is a Silver Salmon Piscomaria with silver scales and a calm voice, despite being a natural prey for sharks. Due to his shy and delicate personality, he is often a target for bullying, but he tries to stand tall using the blue scarf he received from Ginger and the others as motivation. He is socially anxious and has stage fright, but his talent for the violin, chess, and dance is breathtaking. He likes looking after babies and watching sunsets. He is afraid of heights, darkness, and frying pans, and he treasures his Dumbo Octopus pet Jelly and his sister Sylvia, who is in ninja training.

Neon (19, male) is a Neon Tetra Piscomaria with red and blue fluorescent stripes that glow in the dark. His left eye has a spiral pupil that can see ultraviolet light, but he has red-green color blindness. He is a mood-maker and a mischievous bisexual. While he teases Azul and Silver, he often gets countered by Aura, who is weak to surprises. He is the class clown who gets kicked out of lessons, but he possesses the charisma to encourage those who are feeling down. He loves rock music, cola, and games, and often hangs out with his best friend Agnar.

Alex (20, male) is an anthropomorphic Axolotl (an amphibian, but treated as fish-type) with warm white skin and red gills. A genius scientist who became a professor at a young age, his trademark is his white lab coat. He often loses his glasses and is extremely nearsighted. A workaholic strong in science, he frequently collapses from lack of sleep while immersing himself in purifying contaminated water and developing a cure for Bubbles' illness. He is a good cook (especially pancakes) and excels at precise measurements. He is oblivious to Bubbles' crush and tends to skip history lectures to stay holed up in his lab.

Jelly (2, female) is a small, plump blue Dumbo Octopus girl who is the group's pet and a precious friend. Originally a stray, she was rescued by Bubbles and the others. Thanks to Alex's treatments, she can survive on land and is skilled at playing hide-and-seek with camouflage and moving by hopping around. She communicates with squeaks instead of words and cannot spray ink. She loves being near Silver, whom she trusts the most. She enjoys surfing on Agnar's tail and is adored by everyone.

Milky (20, female) is a rare hybrid anthropomorphic creature (Arthropomaria) with the wings, antennae, and eyes of a moth combined with the legs and fur of a ferret. Her moth traits are strong, and she has the ability to glow in the dark. She is energetic, curious, and very social; as a senior at the university, she is always happy to support her Piscomaria friends. She has an older brother and a younger sister, and she is a friendly, big-sister figure who is relied upon by her companions across species lines.