The hippo was longest-serving resident of Manila Zoo, and staff say she was there, aged seven, when it opened in 1959.
Her age cannot be independently verified as the zoo has no paperwork on her origins.
However, the typical life span of a hippo is between 40 and 50 years.
"Bertha was among the pioneer animals here," zoo director James Dichaves told AFP news agency.
The zoo said she enjoyed a diet of grass, fruit and bread.
Its oldest resident is now Mali, a 43-year-old Asian elephant.
Earlier this year, animal rights activists launched a petition calling for Mali to be transferred to a wildlife sanctuary in Thailand.
Bertha - thought to be the world's oldest hippopotamus in captivity - has died in the Philippines, aged 65.