Garudapurana 1.142.2

1.142.2

matsyādikasvarūpeṇa tvavatāraṃ karotyajaḥ /
matsyo bhūtvā hayagrīvaṃ daityaṃ hatvājikaṇṭakam //

The Unborn takes incarnation in the form of the Fish and other [manifestations]. / Becoming a fish, he slew the Daitya Hayagrīva, the thorn in the side of the gods;