I found this under carrying charges and was wondering if I can claim the MER fees paid for my mutual fund investments (both registered and non-registered).

MER fees are not deductible for either type of mutual funds. 

Any fees paid to manage Registered Accounts are not deductible as "carrying charges and interest expenses". Registered accounts include RPPs, RRSPs, RRIFs, and TFSAs.

Investors in mutual funds do not pay fees directly; they pay a management expense ratio (or MER) that’s built in so the fee is implicit. MERs are not disclosed separately on income tax slips or returns as mutual funds deduct the fees and report distributions net of fees.

https://www.canada.ca/en/revenue-agency/services/tax/individuals/topics/about-your-tax-return/tax-re...