Hmmm....well first off...I will use my lfs to check just to confirm my readings. I love my lfs but you still have to remember they are wanting to make money from you. That being said, I would think maybe a tank mate has been hassling him. 7 fish in a 45 is really overstocked. Max in my 45 will be 5 fish. Think one fish for 10 gallons. I feed my tank every other day. Red slime algae is a good indication that you have something in the water. Nitrates, phosphates..something is feeding it. Having the algae in the tank will mask whatever it is eating on a test. As far as the sick fish, I am sorry to say but I think you are correct and he wont make it through the night. Fish can and do get harassed to death by tank mates. I wish I could give you a magical cure for the fish but I cant. Sometime even with the best care and best water quality they die. I hope I am wrong and he pulls through...if it was my tank I would feed less and stop adding fish you are pushing your limit already.
