Rapid Breathing - Cause For Concern?

The cardinals tend to ignore the peas but she was devouring them earlier in the week for what must have been the first time, shortly before her first Epsom salt bath. I fear she may associate peas preceding the trauma of Epsom salt baths, so, if she continues to live, I do wonder if she'll ever eat them again.

I don't actually think there is an internal blockage, though - like the former x-ray tetra, I think she just eats a lot which accounts for her large size, but there seems to be swelling/bloating generally plus the protruding scales.

I only really noticed the protruding scales around the belly initially, and they are most pronounced there, but it's also evident to a lesser extent the length of her sides higher up, if viewed from above - it's almost as though she's squeezed herself in a tight space and 'ruffled' her scales so that they have a blurry look.

Thanks.

Video and photo attached - terrible quality but definitely highlights how pale she is and the raised/ruffled scales.
https:///youtu.be/b0_2wmOdTls

The situation is much the same, I think.

I'd really like to move her into the main tank ASAP as I think the company of her tankmates would vastly help - restore her colour and eating, at least.

However, I think I'm going to have to wait until tomorrow to do so. I need to double the dose of eSHa 2000 as got very soft water, so 4/2/2 drops on Days 1-3.  I was nervous about exposing her to 4 drops at once, though, so gave her 2 drops on 14th late afternoon and the other 2 on 15th morn (effectively that would have been Day 1's dosage), then gave her the next 2 drops on 16th morn and the third and final set of 2 drops this/17th morn.

I think the best plan is probably to leave her in that until tomorrow morning - just hope she survives another night on her own - then gradually dilute the QT over the course of tomorrow by regularly removing the water and replenishing it with the main tank's water, with carbon in the QT's filter. Hopefully, by the evening, she'll be able to be moved across, and, by then, will be expelling less copper-based eSHa 2000 so that the snails in the main tank aren't affected in any way.

Does this sound sensible? I would prefer to have her moved over this evening but would probably need to start the dilution process late afternoon by which time she wouldn't have had the full benefit of the eSHa 2000 course - just 6 hours of the Day 3 dose.

Thanks, all.

The situation each day has been that she looks a little better in the mornings before administering the medication, then, as soon as medication is administered, spends the rest of the day cowering by the filter or at the other end watching her tankmates in the main tank (although this didn't happen yesterday - the entire day was spent by the filter). Presumably it takes almost 24 hours in the latest medication dosage to get accustomed to it.

This morning, she was in the usual morning fettle, moving around a bit more. As I've been diluting the QT back to more standard tank conditions, she's perked up more and more. However, her scales are still protruding - https:///youtu.be/3juqd2bkF50 - and she's still breathing fast and resembles a puffer fish straight on.
 

Thanks, both. Moved her across about an hour ago, in part because Mr FCMF was getting increasingly frustrated with the hospital tank taking up space, water transfers (and spillages), and my instructions not to cross-contaminate eSHa2000 equipment with main tank equipment. Although she looks like she's been through a washing machine on the spin cycle, and is breathing very heavily, she certainly seems to be pottering around otherwise normally, including pecking at bits of food in the silk plants. From a mental wellbeing type perspective, I think it's been a good move.
 

Update:
She's continuing to potter around. Yesterday evening, the other cardinals kept pushing her out of the way when she came near their close-knit group (possibly sensing illness or medication or shunning her as no longer a 'member' of their group) but this is happening less today, and/or she's choosing to swim elsewhere, exploring the silk plants. I'm not sure that she's actually eaten yet. With the ongoing rapid breathing, she may well ingest food. The 'porcupine' look is less marked, and her colouring is only slightly less vibrant than the others. I'm glad I've tried 2 Epsom salt baths plus a course of eSHa 2000. No idea what direction this is going to go but, on balance, I definitely feel I did the right thing by returning her to the main tank rather than extending the treatment regimen which would have elongated her evident stress in isolation in the hospital tank.
 

I've had a good look at her since the lights came on. The bubble seems to have moved location which is odd. She's no better, no worse than she has been since return to the main tank. Her behaviour is similar. She behaves as though she's heading towards food but doesn't seem to actually eat it- possibly still off her food since the medication treatment. She's still paler, especially in the red parts, than the other cardinals; the blue parts higher up on her flanks and the white parts on her underside have a ruffled look as though she's been towel-dried or has a slight coating of something on her*. There is something similar to what I recall from the pygmy cories - it looks as though she has a normal fin and a white stump/pustule where the counterpart fin would be. However, these fins look like extra ones in comparison with the other cardinals - they're between the pectoral and pelvic fins. Another aspect I've noticed is that, when rapidly breathing the other day, the inside of her mouth looked reddish; I wasn't sure if this was normal or not, but, when continuing to rapidly breathe today, it's now pale-coloured.
*Edited to add: on closer inspection of the blue parts higher up on her flanks, it looks as though there's a top layer of clear-coloured scales that are shedding or ready to shed.

I also suspect there was nothing more that could be done. Dropsy generally indicates organ failure so really I think you went above and beyond here. Sorry to hear of her passing nevertheless.

It is always sad when a fish passes but you did the best you could.