Pāṭidesanīyakaṇḍa

Vinayapiṭaka · Parivāra · Vol. 8 · Section 773

[773] One who, having asked for fish, eats it commits two offences (āpatti): she accepts it, thinking, "I will eat" — an offence of wrong-doing (dukkaṭa); for each and every mouthful swallowed — an offence to be acknowledged (pāṭidesanīya).

English translation from the Pali (Siam Raṭṭha edition) — under review, not for citation.

This passage also appears in 2 other places

Vol. 8 · Section 384 — Pāṭidesanīyakaṇḍa
Vol. 8 · Section 675 — Lasuṇavagga