Salmo fibreni, or the Fibreno trout, is a freshwater salmonid fish, endemic to Lago di Posta Fibreno in central Italy.

[1][2] The size of Lago di Posta Fibreno is only 0.29 km².

It is a narrow lake 1.1 km long, 100–300 m wide, situated 289 m above sea level.

The lake is in a karstic terrain and rich in underwater springs.

The Fibreno trout breeds close to these springs in mid-winter.