Fishhouse Punch: Peach Brandy vs Schnapps
What is peach brandy? True peach brandy is really hard to find (and tends to be really expensive). It's brandy distilled from fermented peaches. (It may be unaged - eau de vie - or it may be aged in barrels like regular grape brandy.) Confusingly I think some producers call their schnapps "brandy" and vice-versa.

Anyway, if you substitute peach schnapps for this, your drink may be too sweet - peach schnapps (in my admittedly rather limited experience) tend to be neutral alcohol with added sugar and peach flavoring. It's up to you, though - try it and see. You may just want to add less sugar if you do this.

(If you can't find real peach brandy, it may be interesting to substitute slivovitz - Eastern European plum brandy, which may be aged or not, or some other palinka. It's usually fairly cheap as well.)