I have a 90 gallon tank with one 7 inch Red Spotted Severum and 4 three inch Silver Dollars.Yesterday I obtained a 5 inch female Red Severum(proven to be a female by her being seen laying eggs before).I put her in the tank and almost immediately the larger Severum started chasing the female.Now I'm not sure of the sex of the larger Severum but I didn't expect this to happen.I thought if they were 2 females it would be ok.If they were a male and a female they would likely breed.Right now the new female is hiding behind a leaning piece of slate I had put in the tank.I leaned it so that the bigger Severum could not get to her.When she does try to come out she gets chased back into her hiding spot.Maybe it takes time for everyone to get along?Any thoughts?