What is it? Tried freshwater dip and fish first aid from reefgrow. Finally perished. Had him for 2 weeks in my hospital tank and also wouldn't eat. LRS, mysis, decapods, fish eggs, brine, nothing.
The effects of cyanide poisoning? I've pretty much given up on buying wild fish from lfs and get mine from hobbyists who already have established fish. That's really the only safest bet nowadays.