Hey Guys!
I have finally decided what I am doing with my 3 Male Betta Fish

Currently Dragonfly, and Firefly are in a 15 gallon divided tank, and Maize is in a 1.5-2 gallon Critter Keeper. I HATE having a divided tank and Maize's is just too small! My original plan was to get 3 new, 5 gallon tanks, plant them and then move everyone into them once they are cycled.
New plan! Get 2, 5 gallon tanks and keep the 15 gallon undivided for one of the males. I am thinking of giving Dragonfly the 15 gallon because he is a tail biter, and am hoping with enough space and having it heavily planted he will be happier!
For substrate I am using aquarium gravel. For the plants I am thinking of these (if I can find them all):
Cambomba
Hornwort
Java Fern
Anubias
Süsswassertang
Moneywort
What other fish, or shrimp, or anything

can I add with Dragonfly in the 15 gallon?