Ganciclovir
Ganciclovir has also been used with some success in treating "Human herpesvirus 6" infections.
Lymphocystis
There is no known cure for this virus, though a privately owned fish research & breeding facility near Gainesville, Florida USA has reportedly been able to suppress the virus into remission using the human antiviral "Acyclovir" at the rate of 200 mg per 10 US gallons for 2 days. Otherwise, some aquarists recommend surgery to remove the affected area if it is very serious, followed by an antibiotic bath treatment to prevent a secondary bacterial infection of the open wounds.