SB 8.24.44
so ’nudhyatas tato rajña
pradurasin maharnave
eka-srnga-dharo matsyo
haimo niyuta-yojanah
Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada:
Then, while the King constantly meditated upon the Supreme Personality of Godhead, a large golden fish appeared in the ocean of inundation. The fish had one horn and was eight million miles long.