You Do Need power plug adapter while traveling from Fiji to Bangladesh.

Here is Why You Need An Adapter

The outlet and plug type used in Bangladesh are A, C, D, G and K and in Fiji is I. This is how they look like.

Fiji

In Fiji, outlets of type I are in use.

Type I

Bangladesh

In Bangladesh, outlets of type A, C, D, G and K are in use.

Type A

Type C

Type D

Type G

Type K