Well, 2.5 gallons is way to small for that number of fish. Usually pet stores don't know what they are talking about. I would take the Danios and minnows back.
Bettas: Rose, Sophia, Addie, Ghost, Buster, Holt, Aidan, and Mercutio!
Just my animals: 0.2 Cornsnakes, 0.2 Bearded Dragons, 1.0 Water Dragon, 2.2 Crested Geckos, 1.0 Tiger Salamander, 0.0.1 Tadpole, 0.0.2 Red Eared Slider Turtles, 0.0.1 Map Turtle, 0.0.2 Hermit Crabs, 1.0 Hamster, 1.0 Rabbit, 0.1 Horses, 2.2 Dogs, 0.2 Cats, Chickens, Ducks, Oscar Tank, Planted Bowl, 10 Gallon, 4x 0.5 Gallon, 5 Gallon, and Planted 25 Gallon Tank....Is that it?