Angle fish with ich

Question
I just set up a 64 gal tank about 1 month ago. It has under grave filters,a bubble in the center of the tank,and a outside box filter that runs 200 gal per hr.. I set all this up and let it run for the first week then treated the water with start right ,next I put in about 50 guppies to get the bacteria thing going in the gravel (will remove later) this was going to be an angel tank.I let this run for about a week, I ordered plants (the tank is covered with plants, also has 10 cherry shrimp 10 algae eating snails and 4 skunk biota and bought a few angel fish (8) 4 about the size of a dime and 4 about A quarter size the first night one of the larger angels died and so I thought the angels had ick. They started rubbing themselves against the plants  so I treated them with quick cure for about a 5 days . did a 30% water change and still noticed there was on changes in the fish still rubbing themselves against the plants and other objects. the larger angels swim in the strongest water flow .they eat really good then go back and get in the water flow. I can't see any white spot on any of these fish ,none of the guppies show any sign of the ick . the angles look like they have something wrong with the slime that covers their body .it looks like it is pealing?
Temp is 80,  Water test kit shows nitrate is safe ,nitrite safe 7.5 hardness,8.0 alkalinity, 6.2 on PH. I just added aquarium salt to my tank. I have had fish tanks for 40 years and have never seen anything like this
I really appreciate your help,
Thanks
Willis

Answer
Hi Willis,
One thing I would refrain from at the moment is I wouldn't treat for ich since you say you have not seen any ich appearing on any of the fish. If they truly were infected with these parasites the white spots would have shown up by now. The slime/peeling appearance is most commonly one or two things. It may be a fungal infection instead of parasitical. Fungus can appear as white/gray/ or even clear material on the fins or skin and can be stringy, fuzzy, or patches.

But what you are seeing may be excess slime coat production due to an irritation in the water, either by the medication and/or poor water quality. I have a feeling with the fish rubbing themselves and the slime coat appearance, that this is more likely the case.

Are you for certain your water test results are as they should be? with ZERO ammonia, Zero nitrite, and Nitrates under 20 at least.

I really think your best bet at the moment is to hold off anymore medication and anymore salt as well (I'm not too sure the skunk botias will tolerate salt for too long) and instead, I would start the aquarium on a water change routine of 30% of the water changed everyday and notice if there are improvements on the fishes appearance. Do this for at least a week and take note of their behavior and skin condition.

Oftentimes, the best remedy for fish that are rubbing and have excess slime production are water changes. There's nothing better for them than fresh, clean water.

Please try that and see how they do.

I hope all goes well!
Karen~