I have had my clowns for about 5 years now, they all get along... the true, false and black and white are one family, the tomato and maroon are the other.. my tank size is in litters bought here in japan it comes somewhere between 87-89 gallons...as far as the hippos go..they were being kept in a 50 gallon aquarium the family was moving back to the states and they had to get rid of them...