Agree with what is said above by previous posters.
However, about the slimecoat thing. Flagtails only suck the slimecoat off other fish if they do not get enough vegetables in their diet. They will eat meat, but make sure you provide them with veggie flakes, lettuce, cucumbers, etc. They will not suck clime if offered veggies.
I think I covered feeding, but my guys love to eat anything. Make sure not to keep them in a '' crammped tank'' or where they feel crammped up as they will jump out.
Growth is kind of slow. But in the beggining they will grow 1-2'' a few months then it will start to slow down after 5-7''.
I suggest keeping only 1 flagtail, however I personally Had success keeping five together in a 150. That was only because I had purchased them at once, and they had always lived together. They were in a big tank. But still they chased each other, and their was always the dominant one. Which I have still. I decided to sell the other 3 and keep the dominant and 2nd dominant one. Both now are in seperate tanks. So for what I'm trying to point out to you is this: if you want to attempt a school of these guys please buy three or more. Or like pygo piranhas its either 1 to 3 or 3 to 6.
You can of course school them with silverdollars, tinfoil barbs, bala sharks, etc... like I'm doing! Its cool, with all that flash of silver. My guests always notice the flagtail by his mouth. The guests say he is the coolest fish. These guys are my favorite fish.
I think I covered everything you need to know about flagtail prochilodulis, if you were interested they are in season now so they shouldn't be hard to find.