Since last Saturday, 3 days ago, my zebra danio female hasn't been well. She doesn't eat and had problems staying upright so clearly some swim bladder related problems. She tilts 45 degrees and sometimes even 90 degrees sideways when swimming. Most of the time she sits in a plant and lets the plant support her upright. She also some of the time breathes a bit heavily and then has a break from it for a few seconds. No clamped fins. I fed them normally on Saturday morning and a few hours later she wasn't looking fine. I've put her in a 25 liter hospital tank and have not seen any poop and she looks a little bloated around the belly right in front of the anal fin. I don't see anything else wrong on her physically. We bought her and another female danio 4 weeks ago and they've been otherwise fine.
I started to give her Epsom salt baths on Saturday evening with 1 Tbsp per gallon of Epsom Salt. She was in the bath for 15 mins twice a day. On Sunday I put metronidazole in the tank 100mg for every 10 gallons. On Monday I added 2 teaspoons of Epsom salt in the tank and still gave her epsom salt baths. On Monday I added another teaspoon after a 25% water change and added a bit more metronidazole.
As the tank has Epsom salt in it, I didn't give her a bath today (Tuesday) to avoid extra stress. She seems more tired. Twice a day around their feeding time I've tried to offer some crush pea to her. I boiled it in water in the micro for 45 seconds, peeled it and squished the inner part and put some of it in the tank. I have not succeeded in getting her to eat it.
So she's been fasting 3 days with all the treatment above and no sign of poop or improvement. I'm getting very worried.
Main tank size: 140 L
Hospital tank: (60 L), but I only have about 25 L of water in there.
Tank temperature: 27 degrees Celsius
Volume and Frequency of water changes: Normally once a week about 30%.
Chemical Additives or Media in your tank: Medications explained above, no others.
Main tank inhabitants: There are 7 fish in the tank: 3 Zebra Danios (1 boy and 2 girls), 2 Corydoras (both girls) and two Dwarf Otos (a boy and a girl). Of course this female danio is now in the hospital tank.
Recent additions to your tank (living or decoration): 2 female danios 4 weeks ago.
During the last month we've fed the fish with flakes and pellets. Every second morning instead of dry food they get frozen food: either bloodworm or white mosquito larvae. Their dinner is mini sized pellets and flakes in the evening. In addition we have always zucchini or cucumber for the otos, who seem to really love them.
Could you please advise on if there's anything more I can do or if I've misdiagnosed and it could be something else.