You only need to fund a wallet if you are:
- planning to make a trade
- funding a trade
And even then you don’t necessarily need to fund the wallet. If you take a trade as a “taker” you can just fund the trade from an external wallet. It never has to touch the Bisq wallet, until after the trade. The amount of btc depends on the security deposit as well, it is normally 15% of the trade amount.
You’ll need bitcoin for, the security deposit, trading fees and mining fees.