Yes, it would appear to be a bacterial bloom - that's a lot of fish to put into a tank after only 1 month.
Originally Posted by Corvette73
It wouldn't be a bad idea to put the barbs in another tank simply because they could be aggressive to the rest of your fish but if they aren't at the moment, it's best to keep them in there while the tank cycles & ensure the filters you using for both tanks become cycled - do you have adequate filtration for both tanks? It's best to have enough filtration for double the size of each tank.
Do you have a test kit to monitor your water parameters? You need to take readings for ammonia, nitrites & nitrates because your 20gal is currently cycling and you want to be able to change your water so the ammonia doesn't go above .25ppm
46 gal fw tank with black skirt tetras, neon tetras, spotted corys, cherry barbs, otoclinus, snails & 4 amano shrimp - plastic & live plants
5 gal QT
Remember: Our job is to take care of the water our fish live in