sick red paradise

Question
Hello, I have a 46 gallon bow front w/ plenty of plants, hollow rock, & 2 caves for... 5 kuli loaches, 1 flounder, bout 10 ghost shrimp, a pair M/F cherry barbs, pair M/F mollies, 1 male & 2 female blue rams, 1 male red flame dwarf gourami, 1 upside down cory, 6 emperor tetras 2M/4F, 2 male red paradise, & 2 female blue paradise, yup & been doin great till I saw some flame paradise & had to get 1 female. I don't know exactly who is starting trouble but 1 of my red male paradise has a gash on his side & the other male has developed a black stripe vertical dividing the front part of his head turning pale, & now I noticed the other who has gash is getting the same 2 tone pattern but horizontal. I asked the lady at the store I got em from & she says its a desease & I should cut my loses cuz she seen it before but can't tell me how to cure it & not sure if it will kill all my others. I need advice cuz I really love these beauties & wanna keep em.
I justed moved after noticing this change in their color & gash, so I made sure to use stress coat. I have a penguin bio wheel 200 filter & water is set at 82F & air pump w/ bubble stone.

I've noticed my red flame dwarf is getting aggresive, making me mad cuz their supposed to be timid & chill. I'm thinkin bout gettin rid of him & tryin out another...

Answer
John,

I would have to say that the first problem is that the tank is over crowded. When the tank is over populated, even the most peaceful fish can start to get aggressive. The fish that are going pale are doing so because of stress. As for who the culprit is doing all the damage, you might have to just sit and watch. I am thinking since you said the red flame is getting aggressive that he might be one of the problems. But it could also be any of the males.  Having all the males in the tank will also raise the chances of having aggressive fish. I would upgrade the tank to a much larger one and the fish should calm down. What are your water perimeters? That can also be a cause of normally peaceful fish becoming aggressive.