Śrīmad-Bhāgavatam 8.24.9
జ్ఞాత్వా తద్ దానవేన్ద్రస్య హయగ్రీవస్య చేష్టితమ్ ।
దధార శఫరీరూపం భగవాన్ హరిరీశ్వర: ॥ ౯ ॥
jṣātvā tad dānavendrasya
[jshaatvaa tad daanavendrasya]
hayagrīvasya ceṣṭitam
[hayagreevasya cheshtitam]
dadhāra śapharī-rūpaṁ
[dadhaara shapharee-roopam]
bhagavān harir īśvaraḥ
[bhagavaan harir eeshvarah]
Word-for-word
jṣātvā
—
after understanding
tat
—
that
dānava-indrasya
—
of the great demon
hayagrīvasya
—
of Hayagrīva
ceṣṭitam
—
activity
dadhāra
—
accepted
śapharī-rūpam
—
the form of a fish
bhagavān
—
the Supreme Personality of Godhead
hariḥ
—
the Lord
īśvaraḥ
—
the supreme controller.
Blended reading (Sanskrit + English inline)
jṣātvā tad dānavendrasya
jṣātvā
after understanding
tat
that
dānava-indrasya
of the great demon
hayagrīvasya ceṣṭitam
hayagrīvasya
of Hayagrīva
ceṣṭitam
activity
dadhāra śapharī-rūpaṁ
dadhāra
accepted
śapharī-rūpam
the form of a fish
bhagavān harir īśvaraḥ
bhagavān
the Supreme Personality of Godhead
hariḥ
the Lord
īśvaraḥ
the supreme controller.
Understanding the acts of the great demon Hayagrīva, the Supreme Personality of Godhead, Hari, who is full of all opulences, assumed the form of a fish and saved the Vedas by killing the demon.
Purport
Because everything was inundated by water, to save the Vedas it was necessary for the Lord to assume the form of a fish.
— A.C. Bhaktivedanta Swami Prabhupāda
Gauḍīya Ācāryas
Viśvanātha Cakravartī Ṭhākura
Gauḍīya
Translation
Understanding the acts of the great demon Hayagrīva, the Supreme Lord assumed the form of a fish.
In the form of a fish he killed Hayagrīva. It is understood from later verses that the theft took place the beginning of the Svāyambhuva Manvantara (in the morning). The Lord took this form to benefit his devotees like Brahmā, since only the form of Matsya could save the Vedas. This is the first appearance of Matsya.
My note
Source: vedabase.io