No you don't need one when you get here go to your immigration office and get their requirements for extension and file for residency certificate ask for a letter for bank, go to Bangkok Bank and easily open a bank account
I did with ivory dent in huai kwang bangkok they were excellent I had several teeth removed 6 implants put in and 6 crowns as well as some fillings it was
***
the price of Australia and they paid 1 weeks accommodation in a local hotel