Ash Wednesday and Good Friday are the primary fast days in the Episcopal Church - and in most churches that identify as ‘Catholic’ (the Episcopal Church is ‘Anglican Catholic’, alongside the ‘Roman Catholic’ and the ‘Orthodox Catholic’ Churches).
We are also called to fast throughout Lent. This is interpreted in many ways, but is mostly in reference to food. You’ll sometimes see people ‘fasting’ from social media or ‘negative thoughts’, but the Christian practice has traditionally been about what/how we eat.