Cobalt Blue Sick?

[mthigpen_02]

My wife just informed me my Cobalt Blue Zebra is sluggish and just hanging out by the heater. (I work offshore and won't be home to Tuesday) I had her check for sores, red gills, nipped fins and white feces with a negative on all. I also had her do a 50% water change adding back my rift lake mixture and dechlorinator. My fish are Mixed Zebras (5) electric blue male (1) and Melanochromis auratus (male) (1). Not sure about aggression being the problem but could be. Tank is 55 gallon set up for 2 and half months. Only thing she mentioned was a white slime substance on the inside glass she noticed while scrubbing. Any Ideas on this?

Is there anything else I should have her check?

 

[mthigpen_02]

Any help would still be welcomed as my fish is still hanging out by the heater and swimming sluggish.

 

[mthigpen_02]

I just had my wife buy a new 10 gallon hospital tank. She stole my last one for a Betta. I had 1 fish get beat up this morning. He has white gashes on his side and most of the tank was attacking him when she got home from church. My question is will he be better moving to the new tank and fighting the cycle or leaving him in the tank. I told her to put 10 or 15 pot scrubbers out of sump in the new tank to help. Any more suggestions?