Unusual QT situation

[jim LI]

i have a 46 gallon qt tank, 4 adults, and a display tank 72 gallon, 4 adults. here's my problem, all 4 fish in my qt are healthy, but when I return them to the display tank, they get aggressively attacked by the fish in the display tank. now 1 fish in the display tank is discharging thick white poop. i want to place it into the qt, but since it is only 46 gallons, i am afraid i am overstocking that tank. and i am also afraid that only 3 fish in the display tank will cause aggression in that tank. as of now, i am medicating the display tank with metro at 1/2 tsp, twice a day. any help would be appreciated.

parameters:

ammo - 0
nitrite - 0
nitrate - less than 10
ph - 7.6
temp - 84
60% w/c with aged water every other day

[bluelagoon]

At any time were they all in a tank together and are the QT new fish?Or if not new;why Qt only four.

[jim LI]

There are 2 new fish and 2 original fish in the qt tank. all 4 fish have been in that tank of over 4 months. the reason there are 4 in the tank now, i had 2 fish from the display tank get sick and placed them into the qt , but the aggression was so bad i had to place a divider in the tank. anyway 1 thing led to another and i got 2 new fish to try and spread the aggression. don't ask for detail why i had to get 2 new fish. too long of a story.

thanks