To me an 8" for weather loach is already pretty old, because they usually max out at 10" with a normal lifespan of about 7 to 10 years of age.
Did you or the previous owners keep it at tropical temps?
Weather loaches are not really tropical fish, they come from Asia (places like Korea, Japan, China, even Siberia) and do best with seasonal cool downs, (mid 70s summer, 60sF or lower winter) that mimic the their life in nature.
So if kept at a constant tropical temps, this may have shortened its life.
When I first kept Gymnpgeophagus and other southern S American cichlids, I didn't realize, they were similarly also temperate specie from Uruguay and southern S America, places that experiences a real winter.
At that point in my awareness (or lack thereof) they didn't do well in my tanks, easily developing fungal skin diseases in my constant warm temps.
When I realized the error of my ways and started providing them with cool downs, they were much healthier, looked better, lived longer, and started spawning.
If your weather loach was kept high 70sF temps all its life, this may have been the chronic stress that lead to a earlier death than normal.
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Sometimes those tropical temps create accelerated growth in temperate water species, which may also come at a cost.
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