ALOT lol
Parasitic infections: Protozoans, Flatworms, tapeworms, flukes, nematodes,
Oxygen deprivation according to Temp.
Copper: BAD idea
Bacterial:in cut/sores...treated with antibiotics added to water or orally(best).
medications include dry and wet, but there is SO much that can go wrong its hard to say just one or two.
its late but ill type more later...anything your looking for exactly?