The Compendium of Caraka 1.26.82

1.26.82

tatra yānyāhāramadhikṛtya bhūyiṣṭhamupayujyante teṣāmekadeśaṃ vairodhikamadhikṛtyopadekṣyāmaḥ na matsyān payasā sahābhyavaharet ubhayaṃ hyetanmadhuraṃ madhuravipākaṃ mahābhiṣyandi śītoṣṇatvādviruddhavīryā viruddhavīryatvācchoṇitapradūṣaṇāya mahābhiṣyanditvānmārgoparodhāya ca //

There, regarding those which are used most abundantly as food, we shall teach a portion concerning what is incompatible: one should not consume fish with milk, for both of these are sweet, have a sweet post-digestive effect, and are greatly abhiṣyandi; owing to being cold and hot they are incompatible in potency; because of their incompatible potency they vitiate the blood, and because of their great abhiṣyandi nature they obstruct the channels.