Not sure if this will work but video is here Cosmic swimming struggles

 

I'm sorry these posts of yours were missed.

Any amount of ammonia is too much. Her positive reaction after the 50% water change is an indication to me that you need to do more frequent water changes, starting right now.

Turn off the lights, that will help decrease any stress she's feeling. Her swimming doesn't seem to be all that rough, she appeared to have her tail being blown upwards from the bubbles, but obviously I'm not there to actually see what's going on/compare.

If you wouldn't mind, could you fill in the answers to this form? It provides some more indepth information including the brand of pellet you're feeding et el;

PLEASE READ BEFORE POSTING: Fill out this form so we can...

Many thanks to BF/TFK Member Mike for developing this questionnaire. It is the same form with a few additions. Please copy and paste into a new message and complete this form when seeking help for your Betta. This information and a clear photo posted directly into the thread will help us give...

www.bettafish.com

 

Housing:
How many gallons is your tank? 5 gallons
Does it have a filter? Sponge filter
Does it have a heater? Adjustable heater
What temperature is your tank? 79-80
Does your tank have an air stone or other type of aeration? Just from the sponge filter
Does your Betta have tank mates? What kind? No tank mates

Food:
What food brand do you use? Mostly Fluval bug bites, and frozen daphnia
Do you feed flakes or pellets? Pellets
Freeze-dried? Frozen daphnia
How often do you feed your Betta? How much? Daily, 2 pellets in the morning, one at night, fasted on Wednesdays, daphnia on Sundays

Maintenance:
Before your Betta became ill how often did you perform a water change? 50% every Sunday
What percentage of water did you change? 50%
What is the source of your water? Kirkland brand spring water
Do you vacuum the substrate or just dip out water? vacuum substrate every 2 weeks, squeeze filter into old tank water every 3-4 weeks, off weeks just vacuum out water
What additives do you use other than conditioner? What brand of conditioner? Prime, Fritz 7, and Indian almond leaves (and the tea water. New leaf every 2 weeks)

Water Parameters:
What are your water parameters? Please give exact numbers. If tested by pet store please get exact numbers. "Fine" or "Safe" won't help us help you. Important: Test your water before the regular water change; not after one.

Ammonia: Currently 0 (I test parameters every Wednesday or every other day when sick)
Nitrite: 0
Nitrate: 10ppm
pH: 8.0 (I know this is on the higher side; it raises from off gassing, source water is 7.6-7.8 out of bottle. This number has been stable since starting the cycle)
Hardness (GH): unknown
Alkalinity (KH): unknown

Symptoms and Treatment:
When did you first notice the symptoms?Approximately one week
How has your Betta’s appearance changed? Colour has faded slightly, seems possible there might be red spots on her)
How has your Betta’s behavior changed? Hiding lots, struggling with swimming when back end lifts up, seems lethargic and uninterested, noticed clamped fins sometimes, not coming out when carer appears like usual
Is your Betta still eating? Yes, but not as much
Have you started treating your Betta? If so, how? Breeder box and stressguard
Does your Betta have any history of being ill? None
How long have you owned your Betta? 2 1/2 months
Was he or she ill or suffering some sort of damage when purchased? No

 

Thank you for that. You're in Canada, are you able to drink your tap water?

 

It is safe for human consumption but our city water is not safe for fish. We lost a betta about two years ago after trying to do a slow transition to tap water after coming home from vacation and not having her source water. Our ammonia and chlorine readings are too high to be safe even with conditioner

 

I also got this video yesterday after cupping her. Not sure if it'll help at all.Cosmic cupped

 

The problem is that the water you are currently using isn't mineralized from what I can research about it.

If you are certain you were using the Prime appropriately, and don't want to filter your tap water (I have chlorine as well as chloramine in my tap water. I am filtering it, and adding Prime, and all my tank water parameters are as they should be). ...you will need to find a different source of water that is mineralized.

 

I don't know if any of these help at all with determining if the water is fine, but if it isn't, is there a way I can safely start transitioning? We have a Brita filter so I suppose I can always run tap water through that before priming and putting it in the tanks. Otherwise I can try and search for a new source water. We had previously used the President's Choice spring water but it was causing nitrates to go over 20ppm, and Kirkland seemed the safest brand. I can look at other brands but I'm nervous about our tap water. What it did to Ruby and how quickly was kind of horrifying.
We have one other betta, Daydream, who is in her own separate 5 gallon in a dofferent room and she's doing fine and great. We've had her since April. Same source water, nothing different care wise. We lost our last betta Nightmare after similar symptoms showed up with him. We got him when we got Daydream. He had fin rot and something else going on but I don't see fin rot on Cosmic. Just very similar behaviour to Nightmare before he died. We lost him in August. Might take me a bit to respond again. I'm going to go do a water change.

I don't

 

Cosmic today after water change

Did a 50% change and let her swim around a bit. I still think I see a bit of struggle, like maybe a swim bladder issue, and I'm unsure of the red spot on her side too. It's not part of her colouring and only showed up in the last few days. It doesn't look as raised as it did when I first posted. Screenshot included is from when I first noticed it.

 

This might have some info that's helpful (I tried to get clarification regarding the reference to in-home filters. I'm assuming they mean the big whole-house ones and not Brita, PUR or the ones that can be put under the sink where a cartridge is replaced when necessary.

Hidden Danger in Some Bottled, Filtered and In-Home...

Many members have turned to bottled water (Spring, distilled, purified), RO (Reverse Osmosis) systems, in-home filtration, etc. Many do so because their tap water is not fish-friendly. Keep in mind, in most cases if your tap water is safe for you to drink it is generally safe for your fish. The...

www.bettafish.com

So, I can't tell, Kirkland apparently does a reverse osmosis on the water and then add the minerals back in?

Cosmic seemed back to her old self after the 50% water change

With all this said, since you have one fish that is perfectly fine, the issue isn't the water, at least not in the overall sense. However, Cosmic's clamped fins which I'm assuming relaxed after the water change you mentioned earlier, along with her immediate positive reaction are indicating to me that there's an issue in that tank's environment specifically.

If this were me I'd do more frequent water changes for her.

You might maybe look into adding some Brita water to the Kirkland - the other thing is that this (purchasing bottled water) can of course get expensive. A way to transition, if you decide to in addition to doing more frequent water changes, would be 10% different water/90% Kirkland, and then over time/changes gradually increase the different water ratio.