help!! flowerhorn could be sick with internal sickness!!

[FHCentral]

hi, i have a 3.5 inch female flowerhorn. since a few days ago, i have been feeding her new life spectrum pellets. now, i am noticing white stringy poop coming out of her. At first i think she is sick, but i can't say for sure because she still eats like a pig. She swims around alot and has alot of energy, and her color hasn't really faded or dimmed down.. I feed her new life spectrum pellets twice a day for 2 minutes each feeding. i also feed her hikari cichlid gold pellets for the same amount of time a day. I occasionally feed her freeze dried blood worms once a week as a treat. Could it be her new diet? is she maybe bloated or can't digest food? or is she really sick? i checked her water conditions 2 days before i noticed the white poop and it was perfect, and the temperature is 82 degrees. also, i swapped tanks with a little baby cichlid i had in the other tank because i just bought a new fish. i put the baby cichlid in the same tank with my flowerhorn with a divider of course. i know its not sick because i quarantined it for 2 weeks before i put it in , and it swims happily and eats and doesn't have white stringy poop or anything. so i need advice and help incase my flowerhorn is sick!!