equilibrium issue, swim bladder?

Question
Hello,

I made a stupid mistake, I bought a new aquarium and new fishes and didn't wait for aquarium to cycle, I filled it with 24 hours old water, turn on a new heater and filter and added fishes. I know it's plain stupid since I had a large months old aquarium with enough water to use.

I had some neons, catfishes and Brachydanio albolineatus (blyth). In first day all were fine. A guppy female was ready to spwan so I put a hatchery in this enw aqarium as well. She made about 40 babies.
Next day, a couple of neons died along with some catfish. Then more neons and catfish. I saved all of them into a plastic aquarium but left the babies there. The fishes in plastic aquarium has the same symptoms, they cannot stay in equilibrium and they swirl swim, most of them at the bottom except some neons at the surface. With 4 blyth exceptions all died during next day. Interesting enough the guppy babies didn't show any symptom but eventually about ten of them died but not sure if it was related. I then moved the blyth into a small glass aquarium, setup temperature at 26C(78.8F) and feed them a bit.

Now it is about 4 days after incident, guppy babies are growing, guppy mother that I put back into her initial aquarium looks perfectly fine. Got 2 of the 4 Brachydanio albolineatus recovered without any medicament but still two of them are into serious troubles, they didn't die but cannot swim normally. They do swim but with some effort and tend to swim sideways and occasionally up-side-down. Today I added Sera Baktopur Direct but without visible effects.

Is there any way to help them out and if so would you be so kind to tell me what to do please?

Regards,
Cornel I.

Answer
It does sound like Swim Bladder but Swim Bladder is usually a sign that something else is wrong. It could be simply constipation. If it's constipation, changing the food might cure that. I doubt it is constipation. Is there anything on their bodies? Rapid gill movement? Backwards swimming? Anything out of the ordinary?