Not particularly advertised as a aquarium keeping product...but sure could be!
While wandering about the web searching to the great mystery of "wrasse mucus"
(RE:
Mucus Covering...?) I came across this:
Perils Lurk for Outdoor Adventurers (NYT)
By JAMES GORMAN
"...There is one new development in prevention, at least of jellyfish stings. A new product called SeaSafe seems to protect against jellyfish stings. (Dr. Auerbach is an investor in the company.) It may, he said, mimic the mucus of the clownfish, which is immune to jellyfish stings. It is also a sunscreen..."
Found:
Trident Sea Safe Lotion SPF30
"...Safe Sea not only protects against UV rays, it also protects against marine stingers. The waterproof lotion has patented ingredients that deactivate the jellyfish stinging mechanism. Will protect against jellyfish, medusas, sea lice, sea nettles, and coral..."
Might just be a handy product to have near at hand when working around tanks that have some of stinging creatures...(keep next to that antihistamine for those with possible severe allergy reactions

)
From now on will be a permanent fixture in my dive bag.
--------------------------
FYI
Also in above article (
Perils Lurk for Outdoor Adventurers (NYT))
"... if you go to South America, do not urinate when you are standing in the water. That is how you encounter the catfish of the genus Vandellia, the candiru. The inchlong fish may be attracted to the chemicals in urine or simply swimming upstream. It normally attaches itself to the gills of larger fish to feed on blood.
Unfortunately, for both fish and person, when it finds itself in the urethra it opens its gill covers, and gets stuck. Fortunately, said Dr. Paul Auerbach, who has written a standard text and a popular book on wilderness medicine, huge doses of vitamin C may soften the spines. Then, he said, ''You pass the fish.''..."