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

Here is Why You Need An Adapter

The outlet and plug type used in Canary Islands are C, E and F and in Fiji is I. This is how they look like.

Fiji

In Fiji, outlets of type I are in use.

Type I

Canary Islands

In Canary Islands, outlets of type C, E and F are in use.

Type C

Type E

Type F