Leah, I just came across this post while doing a search of the forums on gourami compatability and although it is an older thread, I want to make a few comments.
I am very sorry for this (and your previous) losses. Your gourami's case was 'dropsy', a.k.a. 'bloat'. It is edema (fluid retention) of the specimen due and is very difficult to treat/resolve once it manifests. In the overwhelming majority of cases, the cause of this symptom in an underlying bacterial disease. The 'pineconing' effect seen in your photo looking down on the fish is very characteristic of more advanced cases.
When you see this case again (hopefully never!), do not waste time deliberating over the possiblity of something this dramatic being
constipation; I see this gastrointestinal malady suggested
far too often for cases where an underlying disease pathology is clearly present and requiring immediate treatment. As mentioned, even with treament the edema and advanced disease progression makes recovery difficult.
Epsom salt has little legitimate use for the therapeutic treatment of fish specimens, IMO... the constipated betta folks might disagree with me but that's OK LOL. Magnesium sulfate is great to raise the GH (general hardness) of aquariums (very handy for those cichlid tanks :grinyes

and that's about it. In fact, the osmotic imbalance created by such a bath can be extremely traumatic for the specimen (even with underlying edema) and futher contribute to demise; it can actually promote water retention in certain cases. The real goal is to treat the underlying infection, not the symptom (i.e. swelling).
In general, the advice of, "Just add ______ salt to your aquarium" is
grossly over-advised. Salt addition has great use for certain conditions (including the treatment of Ichthyophthirius (a.k.a. 'ich') along with an increase in temperature, but please take any advice for adding salt to the aquarium with a 'grain of salt'
