1. Neon Tetra (Paracheirodon innesi): This is the most common "neon fish" and is what people usually refer to. It's a small, slender fish with a distinctive bright red stripe that runs along its body from its eye to its tail. The stripe is bordered by a bright blue-green stripe, making it look like a neon light. It has a transparent body with a slight yellowish tinge.
2. Cardinal Tetra (Paracheirodon axelrodi): Similar to the Neon Tetra, the Cardinal Tetra has a similar body shape and size. However, the red stripe extends all the way to the tail fin, and the body is more silver/gray than yellowish.
3. Neon Rainbowfish (Melanotaeniidae family): This is a larger group of fish that includes many species. While not all are neon-colored, many have vibrant colors that can resemble neon lights. They can range from bright red and orange to blue and green. They tend to have elongated bodies and are known for their iridescent scales.
4. Other Neon-Colored Fish: There are many other fish species with neon colors, such as the Neon Danio, Neon Goby, and various species of Cichlids.
To be more specific, can you tell me:
* What color(s) are you thinking of?
* What size fish are you interested in?
* Have you seen a specific picture of a fish you'd like to know more about?
This will help me give you a more accurate description!