I have a male betta that I keep in my office at work. I've had the little boy for almost a year now I think and I've noticed something really weird lately. He seems to do worse when I clean his tank than when I let it get dirty. There have been times where I clean is tank and for the next few days he acts like he's dead, but once the tank starts to get dirty again he perks right back up. This seems counter intuitive to me, and I'm wondering if anyone knows what might be going on. This isn't my first betta, but it is the first one to act like this.
Are you using a dechlorinator/water conditioner? If not, that might be an easy reason why. Our treated tap water is not great for any fish unless you either leave it sit out for a few days or treat it with a water conditioner. Betta fish also stress out easy so that might put him into sorts. Just a couple things...
The tank doesn't have a filter. It's a small half gallon tank. When I clean the tank I remove him and then scrub everything down using hot water and a sponge, no chemicals. Then I refill the tank with luke warm water, add the water conditioner, give it a minute and then add him back into the tank. There isn't really a way to clean the tank properly (replacing only 50% of the water) like I used to do with my goldfish because the tank is so small. I hadn't considered that cleaning his tank might be stressing him out. Is there any way I can do it that would be less stressful for him?
What has worked wonders for me is to get a few Indian Almond leaves, pinch off a section a little larger than a quarter and toss it in. The tannins help fight off bacterial infection and fungus. I was a notorious betta killer in the past and my guy is over a year old now and looking fantastic!
I still have to clean his tank once every two or three weeks, but you can have your replacement water already conditioned with the leaf in there so it's not much of a change.
I have had your same problem with many of my late bettas, clamped fins, lifelessness etc after cleaning the bowl. Try the Indian Almond or even pesticide and fertilizer free (dead and brown) magnolia or oak leaves. They just benefit from the tannins.
0.5 Normal (.Cleo,Peaches,Oprah,Big Stripe,Big Girl)
1.1 Spider (Xander.Nagini)
1.0 Butter (Aidan.)
1.0 Pinstripe (Monty.)
1.1 100% het pied (Lestat.Akasha)
1.0 100% het genetic stripe/albino
0.1 Pastel (.Charlie)
0.1 Mojave (.Suren)
1.1 Yellow Belly (Louis.Claudia)
0.1 Pied (.Cherry)
1.0 Pastel 66% clown (Lemangelo.)
1.0 Desert King (Apep.)
0.1 Snow Corn (.Bailey)
0.1 Hog Island (.Maddy)
0.1 P. brongersmai (.Jillian)
Is the water room temp or "lukewarm"? Lukewarm would be warmer than the room temp water, and you may be stressing him with a temputure change as well as whatever is in the water. You can buy a gallon of distilled water at the store cheap, leave it under your desk so it's the same temps.
The Indian leaves are helpful, a live plant might help him also.
What are you putting him in while you clean? What kind of sponge is it? Many of the kitchen sponges have sulfacates(sp?) in them already since they are designed to be used with dishes and kitchen cleaning. A paper towel might be better.
No Legs and More
"Stop being a wimpy monkey,; bare some teeth, steal some food and fling poo with the alphas. "