aside from keeping the water pristine, i'd add 1 percent salt to the water. this will mitigate the effect of fluid loss through open wounds resulting in osmotic stress.
table salt is just fine. it's sodium chloride and that's what you're looking for. it's a myth that iodine and/or flow agents in table salt is bad for your fish ... there isn't enough of either agent to harm an amoeba let alone a fish.Please not table salt.
the fish would die from extremely high salt levels before the iodine could even affect them.Please not table salt.