Re: Is this dropsy/swim bladder?
#4
Frozen pea ( not pee, though, as it's ammonia!
) is absolutely fine but it's easier to take the shell off if you pour a tiny bit of boiling water over it first to 'blanch' it - the shell should then slide off easily.
I would definitely focus on ensuring that ammonia and nitrite are 0, and nitrates no more than 20 above tap water levels - so do whatever frequency and amount of water changes are required to ensure that the water quality is consistently at that level.
That sounds fine for a hospital tank. Water in the hospital tank needs to ensure water quality is the same as described above, and the same temperature as in the main tank. Remove a small portion of media (sponge/foam) from the main tank's filter and put it in the hospital tank's filter, to ensure that the hospital tank is instantly cycled.
An Epsom salt bath might be a plan if the scales start to protrude any further. Alternatively, a bacterial infection treatment (e.g. Waterlife Myxazin or eSHa 2000) might get to the root of the problem if it's bacterial. However, I would concentrate for now on the pea treatment plus optimum water quality, then let us know how the situation is tomorrow.