Thanks for the article. I am doing a 25% water change today then treating tank with Metafix. Going to get rid of charcoal in filters too. Not sure what if anything is still in tank, but an overall treatment is in order now. Last night I ended up getting rid of the two balas and one angel fish that had gotten itself into the filter tube inlet holes. He wasn't doing so good, swimming in circles or just floating with the current. Used frozen water to let them go quickly also. All other fish are normal and healthy, but still going to take some precautionary measures to make sure all is ok with tank.