+1 You need 4+ girls and for them you will need tons of plants and caves to escape aggression. To have 4+ girls you need a 10+ gallon aquarium. It just doesn't work with the smaller tanks because the ammonia will build up so fast you'd be doing daily water changes, filter or no filter.
Feel free to message me any questions, I'll try to help the best I can!
Rummy- Mini Rex Rabbit
Diz jr- Betta
Yoshi- Crested Gecko