Can Cold Water Do This To Betta?

[casshyr]

Here's the background:
My betta recently had fin rot, around 2 weeks ago. I've been adding tetracyclin, melaflix, metabolic boost, betta conditioner religiously, and over the past week, it looked like it has fully recovered.
Today, I just did a complete water change. After 4 hours, I noticed my betta fish's fins seem to be splitting apart, like as if it just got fin rot. But there's no way this could be fin rot right? cuz 4 hours ago, it was totally fine.
And I don't think this is self-induced either, since my betta doesn't have that behaviour history. And there are no sharp rocks or anything that he might cut upon. And I don't think the water is unclean either.
My only suspicion is it could be the cold water, which I made the mistake of not heating it up first before I add in the betta. The temperature was around ~23 degrees when I re-introduced the betta. Could this be the reason why suddenly my Betta's fins are splitting apart?

I am now turning on the heater.

So my main question is: can cold water caused betta's fins to split apart, similar to the symptoms of fin rot (except without the black dots)?

 

[Bluu]

Hi, I don't think cold water alone would be the culprit for split fins. 23 Degrees is a little chilly, but the Betta would be fine once the temperature got to 25-28. Do the fins have a tear in them, that makes the tail fin appear like its two parts? If so, he probably tore them when flaring (as this is a sign of over flaring) if there is nothing in the aquarium that could be sharp enough to tear them. It's possible that his fins were particularly delicate after the fin rot.

My advice at this moment would be to keep an eye on him, keep up with the water changes and continue with a few more doses of the fin rot meds (even though his fins appear to be healed), just to make sure it doesn't come back to the recently split fins.

 

[loraxchick]

hes been medicated enough. id give a break from any and all meds for a week or more before considering another round.
while cold water doesnt cause finrot, if the drop in temp as quick and significant it could lower their immune system from stressing them out. that would allow whatever bacteria is causing his finrot to resurface and take hold. overuse of antibiotics could lead to resistant bacteria. i would not suggest any more meds at this time, instead clean clean water and high protein foods (like frozen bloodworm 2-3 every other day)
and yes, finrot can take hold that quickly depending on which bacteria is at fault and how healthy the fish's immune system is.
i would not rule out as stated above split fins tho (from being thin and weak)
is it possible to put up a pic of the damage?
all the best!
cheers