Is this Aro in the same tank as the TSN?
Seems kind of odd that you are posting about two of your fish that appear to have the same symptoms as if they are completely unrelated.
To get some better feedback, please answer the following questions:
How is the TSN doing?
Are the Aro and the TSN in the same tank?
How large is the tank?
What are you using for filtration and at what flow rate?
What are the water parameters in the tank (AMMONIA, NITRITE and NITRATE)?
How often do you do water changes?
How much water do you change during your water changes (please answer as a percent of the overall system volume, or tell us how large the tank is and how many gallons you change)?
What are the NITRATES at right before you change the water (you need to test this before every water change to monitor if it is under control)?
Are there any other tank mates with the Aro and/or the TSN?
What is your feeding schedule and how much of what do you feed?
Are the fish in question eating ok?
Let's start with these and if you can provide this information then I'm sure that you will be able to get a lot of helpful advice.