A hydrocoele is a collection of fluid around the testicle (testis), in the tunica vaginalis (the space surrounding the testis). Hydrocoeles only occur in males. Typically presents as a painless swelling of the scrotum. Most hydrocoeles are congenital (ie. present at birth) – these are usually seen in boys aged 1-2 years of age. Most congenital hydrocoeles resolve by the end of the first year of life. Persistent congenital hydrocoele is readily corrected surgically. Secondary hydrocoeles can affect males of any age, but usually occur in men older than 40 years. May affect one side of the scrotum or both sides.