Quick-onset acute body rot?

[FiddleSticks268]

I bought two tetras last week and since, they have both died. All of a sudden I come home one night and my betta's fin is completely rotted off and he has about 2 mm into his body of body rot. At first I thought I was just a bad fish owner and just didn't notice until then. But then about 6 hrs later when I got up for work he was dead and an entire 1/3 of his body was covered in rot. With this time scale he probably got sick the day before some time in the afternoon and in less than 24 hours just died. I don't know if it's a disease the tetras brought in? I don't have a way or room for a way to quarantine fish and I've never had a problem until now! Has anyone heard of a quick-onset body rot that could kill a fish this fast? My other fish are fine--I have 4 tetras left, 3 ADFs, and 1 cory (the petstores are all sold out--I know I need more). I treated my tank (20 gallon long with sand substrate and live plants, around 75 degrees, a 40 gallon underwater fluval filter) by turning the heat up to 80 and about 1 tsp of aquarium salt per gallon. Will my fish and plants be okay? I just want to kill whatever bacteria killed my poor betta and those tetras :(. I think tonight I will do a 75% water change unless I need to wait longer. Here's a picture of my betta: https://lh3.googleusercontent.com/-A...k/IMG_0005.JPG. I did a water test with 0 ppm of both nitrite and ammonia.

[Myates]

I'm sorry for your loss :(
Hmm.. it looks like it, but the rot that attacks the fins and then the body usually happens over a long period, sometimes months, before it gets to the body.
On the other hand, tetras are notorious for eating fins.. and could of did a number on him and stressed him out to the point he passed away. I only say that, as there isn't rot any where else.. but that isn't always the case.
But you are right, the body looks as if the rot had attacked it, which again, even rot on the body tends to take a bit.
Never seen something like this happen this quickly.. unsure what to say other than you will want to a water change on the tank.

Your plants may not like the salt, most of the time the salt will harm/kill plants.. your tank should be kept closer to 80 all the time - 75 is a bit low for tropical fish.
AQ salt you should not use for more than 10 days, daily water changes will be needed during treatment.

Rot happens if the water quality isn't as good as needed, along with damage to fins - needs damage to form.

How often do you do water changes?
The % of water being changed?
Additives?

[FiddleSticks268]

Originally Posted by Myates

How often do you do water changes?
The % of water being changed?
Additives?

I've been changing the water quite a bit. I've had this problem with a film on top of my water for a while now--I think it's because I added gravel a while back that wasn't rinsed well enough. It ends up being about 25% every 3-4 days to get the film off. It's been a few months though and it didn't seem to be a problem so I don't think it is the problem now. I add a water conditioner by tetra with like Bioextract or something? Also a liquid fertilizer but I've been using it for years with no problem to any of my other bettas.

[Myates]

Hmm.. the film sounds like it just may be excess protein that builds up sometimes in tanks - a film to even a thick goo like substance. Can skim it off with paper towels if needed. Harmless, so it shouldn't of caused it.

Only thing I can think of is some sort of bacterial infection that moved quickly - as you stated. If you were doing weekly water changes prior to upping it, then that is the what I would guess to of happened.. maybe OFL or Sakura8 will pop in and may know something.. I've been out of the fish disease loop for quite a few months, so still pushing out the cobwebs.

[Tikibirds]

There is the "mystery disease". I think all the bettas that have been reported on here have been some shade of blue and have died in less the 24 hours. It seems to start with the end of the tail fin and then rapidly reaches the body.

I think someone caught it early and managed to fight it off with Kanaplex

Here is the stickie
http://www.bettafish.com/showthread.php?t=90086