SB 8.24.4

śrī-sūta uvāca
ity ukto viṣṇu-rātena
 bhagavān bādarāyaṇiḥ
uvāca caritaṁ viṣṇor
 matsya-rūpeṇa yat kṛtam
Synonyms: 
śrī-sūtaḥ uvāca — Śrī Sūta Gosvāmī said; iti uktaḥ — thus being questioned; viṣṇu-rātena — by Mahārāja Parīkṣit, known as Viṣṇurāta; bhagavān — the most powerful; bādarāyaṇiḥ — the son of Vyāsadeva, Śukadeva Gosvāmī; uvāca — said; caritam — the pastimes; viṣṇoḥ — of Lord Viṣṇu; matsya-rūpeṇa — by Him in the form of a fish; yat — whatever; kṛtam — was done.
Translation: 
Sūta Gosvāmī said: When Parīkṣit Mahārāja thus inquired from Śukadeva Gosvāmī, that most powerful saintly person began describing the pastimes of the Lord’s incarnation as a fish.