Tiger Barbs Flicking

[rust81]

I've just setup my 2nd tank (its only a 50L) and i have 6 baby tiger barbs only in there. They are currently only about 3/4 inch. Before introducing these to the tank i did a fishless cycle for 4 weeks and waited until ammonia and nitrate were both clearing to 0 within 10 hours.

So far the barbs have been in the tank for 2 weeks and are doing well. However tonight i have noticed them flicking against one of the terracota pots i have in the tank. They seem to swim by it and just rub their mouths or the sides of their bodies against it. Here are the stats of my tank below;
Size: 50L
Plants & gravel: Plastic plants and Roman Gravel. 2 terracota pots and 1 ornamental bridge
Ammonia: 0
Nitrite: 0
Nitrate 5 - 10 ppm
pH: 8

I'm wondering whether i should treat with methalyne blue as i recently purchased some just in case, or should i wait to see what happens in the next few days? The fish dont seem to be removing any of their scales when they are rubbing against the pot - so i'm wondering if this is anything to be concerned about?

 

[*Fishkies*]

Do you see any small white spots on them? It will look like salt was sprinkled on them.
ICH Treatment

 

[rust81]

Thats the thing - they look completely fine. There are only 6 of them in the tank and they all look fine. They all rush to the top of the tank to feed. I've just done a 20% water change in case there was anything in the water. I'm loathed to start treating on the off chance that they actually have ICH. Any ideas?