Multiple bank account

if your income, without claiming deduction is below taxable limit for the year
it is not mandatory to file return for the year

details of bank accounts can be declared in income tax return.
if you want to file return, you can declare

other wise not possiable to declare and you are not liable also

It is not mandatory to fill the tax for you if your income is fall under the limits.

There is no necessity in Income Tax to declare your bank accounts other than filing of filing your income tax returns.