I have no example to offer where ika has been used in reference to some star (other than sun). That may be due to the difficulty in identifying specific stars in the rongorongo texts.

To summarize: Only sun, moon, and Saturn have been found connected with ika.

Waxing moon was regarded as a 'rising fish', meaning 'growing', and waning moon with a descending (upside down) 'fish', declining in light.

This structure was then used also for the 'phases' of 'waxing' and 'waning' sun - for the season when it grew in strength, was revitalized, respectively the season when it faded away.

Saturn is another matter, this 'pale star' was connected with the fading end of the week, and therefore was the opposite of sun. The opposite of sun ('fire') is water, the element for fishes.