SOLVED. Book about dangerous creature in a river. [s]

[Steve]

Read a book about 15 years ago. It was set on a newly colonised planet. Told the story about large dragon like creatures that live In the rivers, also other fish like creatures.

After settling on this planet, the smaller fish enter the next stage in their life cycle. They change into smaller versions of the dragon creatures. They come out of the river to feed on each other and anything else they can.

The story then becomes a way to survive. In the end the characters are saved by one of the dragons, who becomes intelligent.

Can anyone help with the title please?

[Sue]

Perhaps the Heorot books by Larry Niven?

This is the first one I think, Legacy of Heorot

[Steve]

Sue wrote: "Perhaps the Heorot books by Larry Niven?

This is the first one I think, Legacy of Heorot"

Thank you very much for your help. This is the book that I was looking for.

[Kate]

A good book -- intense.