If the goo is too salty, probably bacterias can grow enough to eat the cause of the bad smell, in particular https://en.wikipedia.org/wiki/Trimethylamine

From a random google search I got this report https://uvadoc.uva.es/bitstream/handle/10324/18877/TFG-I-468... (mostly in Spanish, with an English abstract). It looks serious and as far as I understand it makes sense. They recommend to add iodine to burn/oxidize the trimethylamine or use bacteria and bubbles or air/oxygen, or a mix or bacteria+algae+light that produces the oxygen inside the mix. It looks like without an active source of oxidizer, the mix will be stinky for years.

This is not rot, but digestion. The digestive enzymes of the fish keep breaking down amino acids, producing the characteristic smell. The salt prevents most microorganisms from growing.