I'll do just the betta names:
Mushu - My fiance named him after the dragon in Mulan
Skerries - Series of small islands
Archipelago - other series of small island
Hu - Thai for "ears"
Lillith - Consort of Diablo
Diablo - Red and Black fish, reminded me of the video game
Don Quixote - scraggly and skinny, and the name was reaffirmed after he took to flaring at Mikel lol
Dory - She seemed to "forget" who she'd just flared and postured at, and she's blue.
Takhisis - she reminds me of a dragon, and that was the only dragon name I could think of.
Oddball and Sedna, who are still with Aemaki: Oddball was the "odd fish out" with a split ventral, until Aemaki found another girl with split ventrals, Sedna is the eskimo goddess of sea cretures essentially.