Yesterday morning my Betta, Olly, whom I had owned for a short span of four days passed away.
When I purchased him he was sluggish, had a "jagged" tail and overall didn't look too great, but years back I had purchased a similar Betta and within a week of coming home and being in a tank he began to look up and lived a long, healthy life--so I figured it'd be the same with Olly.
Long story short, he never ate (and according to online searches, people had similar issues and it was caused by the stress of coming into a new tank and within days to a week their fish would begin eating). By the second night he was just lying on his side at the bottom of the tank, which I felt was abnormal. I did online searches and again, some people said it could be due to stress. I got opinions from friends who had Bettas as well and they said it was just stress and I needed to calm down. I poured out some of his water so it'd be easier for him to surface and he actually started swimming more.
By the third day he was still sluggish, but moving around. There weren't any other physical signs of an illness, but I still had some "instinct" that figured something wasn't right--and by 10:30pm when all aquatic stores and chain stores such as Petsmart or Petco had closed I noticed a cotton-like string hanging from Olly's gills.
I did a thorough search and with all the information I could gather, it seemed as if Olly had Columnaris. On the fourth morning, as I was preparing to leave to get medicine I decided to quickly check on him one last time and he had passed away.
I assume he already contracted the disease, but when I brought him home and placed him in warmer water it made it progress.
Now, I completely stripped down his tank: took the gravel out, tossed the decorations, etc.
I bought a new heater, thermometer, decorations and still have half a bag of gravel--so the only thing left is the tank.
I know I probably went overboard tossing everything out, but better be safe than sorry.
My main question is: If I bleached the tank, would it rid of any residue from the (potential) Columnaris that my Olly had? Or do I need to toss the tank and buy a new one altogether?
^I feel as if I should know this, but this is the first illness with any Betta I've owned and the first death that wasn't due to natural aging, so I'm a bit nervous about getting a new fish and placing him in the old tank if bleaching if it isn't going to get rid of the disease.
Thank you in advance for all that can/try to help! I really appreciate it!