I had a columnaris outbreak in a 10 gallong that I re used some old gravel in. It killed one female who I isolated in a cup within 24 hours. It killed another one before I even saw signs of it. I pulled the third female and have housed her in isolation for a month now. I had a couple clamps holding a sprig of philodendron in the aquarium water to propagate it and without even thinking I stuck it in the bowl of my white crown tail. In about a week he was acting funny, always on bottom or up top, I thought he had swim bladder. I started treating with epsom salt and within 36 hours he was dead. I hadn't even heard of this disease before then but I educated myself QUICK. Sadly I had taken that same sprig of philodendron (now planted LOL) and placed it in my King Betta's jar when I did the isolation for epsom salt treatment
When he started getting lethargic, clamped and showed a white tuft I started treatment asap in the form of tetracycline and Jungle Fungus cure (this should cover all gram pos and neg bacteria). I had already mixed this up to treat a female I picked up from Wal Mart who was COVERED in something I'm assuming was columnaris and fin rot.
Fast forward a few weeks and I notice my smallest crown tail female who came from the sorority and has been in her own container for a few weeks now has white tufts. I figure it's just her shedding her slime coat so I swap her into 100% clean water 2 days in a row. The next day I see her slamming her mouth and face into the rocks and 12 hours later she has a massive outbreak of columnaris! This stuff can stay dormant for ages it seems like! She's now in an isolation cup, reduced temp, brand new batch of tetracycline, jungle fungus, and 2 tsp of AQ salt per gallon. She's chubby so she'll be fine with a fast and man she must be tough because this stuff just murdered the other bettas that caught it
SO now I'm going through every container, they're getting a soak in some oxy clean and water. All of the gravel is being boiled in iodized salt water as we speak. Every aquarium plant is getting soaked as well. I'm considering throwing a couple pots of boiling salt water in the sink with all of the containers/nets/etc. Are there any other things I should be sure to clean/check while I'm at it? I think I have all bases covered but I would like some confirmation.