I have a 10 gallon tank with 6 bumblebee guppies (started out with briny water but they are doing better with no salt), 2 dwarf puffers and two ADFs. The tank has been going for 6 months and everyone is fine.
I feed them all live blood worms and I call it my little tank of cute monsters. I have 3 other tanks and this is the only tank I have never had problems with.
I have lots of plants and caves, but everyone likes to hang out in front looking for food.