search for google "aquarium plants killing shrimp"
one forum made an inquiry on this with a plant distributor located in the UK that was shipping plants from taiwan (i think).
for international shipment of plants, animals, produce, meats, ... anything that 'could' carry anything other countries may not want released into the wild, (diseases, parasites, pests, etc.) the country producing/raising the critters or food has to have it treated to be classified as safe for international transport
how these things are treated is decided by the country of origeon.
so if the country that is exporting is useing chemicals that are banned in the recieving county, ... well you plants have been treated so it's safe.
those chemicals in a fish tank, ... well you could loose all your fish, ... but aquariums are expected to have fish, so they don't use toxins that are expected to be dangerous to fish.
your inverts, well they're part of what international regulations are concerned about, so your shrimp are expendable, ... if you have live food, they're even more susseptable, and could be garanteed to be gone within hours.
it's an educational interesting read if you find the articles about it.
the forum that inquired with the UK distributor was appearently shocked enough they stopped buying from the company in taiwan, they also stopped adding their own "additional" treatment to plants they were dealing with.
"You cannot understand a system until you try to change it."