SB 8.24.10
tatra raja-rsih kascin
namna satyavrato mahan
narayana-paro ’tapat
tapah sa salilasanah
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
During the Caksusa-manvantara there was a great king named Satyavrata who was a great devotee of the Supreme Personality of Godhead. Satyavrata performed austerities by subsisting only on water.
Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
The Lord assumed one fish incarnation to save the Vedas at the beginning of the Svayambhuva-manvantara, and at the end of the Caksusa-manvantara the Lord again assumed
the form of a fish just to favor the great king named Satyavrata. As there were two incarnations of Varaha, there were also two incarnations of fish. The Lord appeared as one fish incarnation to save the Vedas by killing Hayagriva, and He assumed the other fish incarnation to show favor to King Satyavrata.