Got to agree its the barbs. I had to same about 15 neons, 2 glass cats and I lost count of the shrimp turned out it was my betta he wont live with anything so he got moved and is in solitary now in his very own 35 litre and the antisocial devil has never been happier.
Saying that though I took...
Probably right on the stress but beware if it starts to look a little like cotton wool then it could be white spot but monitor it for a day or 2 as you don't want to go adding any treatments unless you need to.
Welcome to the fishy fold.
Anna
The main thing I would say is get your stocking levels down or get a bigger tank the tank is very overstocked and the problem will reoccur if you don't, be careful with your plec as depending on the type it could grown quite large may not be big enough. I am surprised your colwn loach are...