Yes fin nipping and Danio's, all danio's need a minimum of a 20 long tank if not bigger. They are very active swimmers and will pace your tank all day! So being a 2 gallon...yeah they wouldn't be very happy lol. There's really nothing else you can put it tanks that are smaller than 5 gallons. You could do a young Nerite snail but eventually they'd grow up all the same...so yeah.
RJ (H. Lifalili), Acara (EB)
Ghost, Trip (Angels)
Leopards: 2:3 Hawkeye, Cullen, Luna, Astrael, Dorian