Another Eden: W.D. Pereira

Matched by a computer, married with 5000 other emigrants from over-populated Earth, Len and Nora Hichens set out for Domus, described as 'Another Eden.' Five years in a space ship and three children later, the arrive on Domus - a planet of poisonous roses, seas full of deadly fish, birds with axe-like beaks designed to split open human skulls and giant cats with strange telepathic powers.  The settlers  survive as best as they can and succeed in raising their families - until they are attacked by aliens. The reason the aliens have come, and how Domus becomes a deadly planet is the climax of this thought-provoking SF tale.