From Starfy Wiki
- Starfy is neither a star or a starfish. When TOSE are asked whether Starfy is a star or a starfish, their policy is to respond that he is neither.
- Starfy made a cameo as an elusive enemy named "Starfish" in the Nintendo DS Mario game Super Princess Peach, likely because Super Princess Peach was co-developed by TOSE and Nintendo.
- In Densetsu no Starfy 3, Wario from the Mario series and his own Wario series makes an appearance as an ally of Starfy, where he helps him get through the Undersea Ruins with three of his transformations; Flaming Wario, Bubble Wario and Puffy Wario. He also teaches Starfy's equivalent of his Ground Pound ability; an enhanced version of the Shooting Star ability.
- Konk, the first secret boss of the The Legendary Starfy is actually a recurring character and enemy/rival of Starfy in the Legendary Starfy series who has acted as the first boss in every Japan-only game.
- In Mario & Luigi: Superstar Saga, Starfy makes a cameo appearance on a movie poster titled Legend of Stafy.
- During the year 2000, Densetsu no Starfy was planned to be released for Game Boy Color but the game was re-built for the Game Boy Advance, with a few differences. Known differences in the gameplay of the Nintendo Space World 2000 trial demo include "Kyorosuke" originally being called "Kyororon", the inclusion of a working debug menu, the apparent lack of the Extra! screen and a different design for doors.
- In the Japanese version of Donkey Konga, one of the available songs is "Densetsu no Starfy". It is actually the Legendary Starfy series Title Song (also known as Tone of Ocean) sung by Becky. Tone of Ocean is the main theme of the The Legendary Starfy series.
- In Densetsu no Starfy 4, there is a Special category costume (one of the Stuff) for Starfy and Starly called Princess and Umbrella that is based on Princess Peach. Starfy or Starly also holds Perry, the parasol from Super Princess Peach.
- The costume was one of the winning designs of the Wanted Kisekae contest, a contest where people would send in their designs for Stuff to Nintendo's headquarters, with a chance of the designs appearing in the final game in some way, either as one of the actual Specials or in the Staff Roll 1. "Princess and Umbrella" was designed by Eriko Kawashima.
- Starfy, Starly and Moe own a Wii, known as the "Fii" with a game resembling Wii Sports in the Densetsu no Starfy R manga.
- Satomi Kōrogi, the voice actress of Starfy and the Mermaid is also the voice actress of Pokémon such as Pichu and Togepi.