Spontaneous fish combustion

Well there's a new one.

Until relatively recently, some believed that domestic chickens were the most abundant vertebrates on the planet with numbers estimated at around 24 billion. In fact, this figure is dwarfed by some fish in the twilight zone. The global bristlemouth population is so vast, for instance, that numbers may lie in the quadrillions while various estimates of lanternfish suggest that their biomass alone is several times greater than the entire world fisheries catch.

South Africa has long had an eye on exploiting the vast lanternfish community living in the twilight zone off the African continental shelf, to try and relieve the pressure on dwindling conventional fish stocks. However one of the country's very first attempts, in the mid-1980s, to build an experimental fishery offshore in the Atlantic yielded an unexpected problem.

Lanternfish have an extremely high oil content, making them very hard to handle. Once the catch was aboard, it spoiled quickly in the high tropical temperatures, and began to degrade dangerously quickly. The temperature rose to such a high level in the decomposing fish that they spontaneously caught fire. An uncontrollable blaze swept through and destroyed the entire fishery plant.

From there the article goes into why harvesting quadrillions of fish from the depths of the ocean in a largely undisturbed ecosystem would, as you might expect, probably be a very bad idea.
http://www.bbc.com/earth/story/20170113-the-race-to-fish-the-larder-living-in-the-twilight-zone