I read this novel at least 15 years ago, but of course it might be older.

A group of people, probably an exploratory scientific expedition, arrives on a newly discovered Earth-like planet. Almost Earth-like gravity, breathable air, water, everything. They settle near a beautiful lake, full of fish-like creatures which are edible to humans (rather improbable, but it is essential to the story).

Alas this idyllic situation is disturbed when a horrible monster attacks them. It is apparently attracted by the humans as a source of food. I am not sure if anyone is actually killed, but it does maim one or more of the settlers and disappears very rapidly.

The people prepare defenses against it. I forgot the details but eventually they manage to kill it.

At some point the POV switches to a pseudo-fish. The vegetation it has eaten so far suddenly does not taste like food anymore. It starts to consider the other "fish" around it as a possible alternate source of food. I am not sure whether this particular "fish" is the first to attack its neighbour, or if it was attacked and eaten by one of them before it makes up its mind. But very rapidly the lake is the scene of a huge cannibalistic orgy.

The "fish" start to metamorphose, like tadpoles growing limbs, turn into smaller copies of the monster and move out of water, just like now air-breathing frogs. They keep eating each other, growing very fast and when they discover the humans, they turn against them.

They are still smaller than the original monster, of which, of course, they were the larvae, and easier to kill. But there are many, many of them and the battle is fierce. The do eat their own killed and wounded, but it only makes them grow faster.

I think that some humans survive at the end, but they suffer a lot of casualties.

I don't remember what happens at the end. I suppose the survivors flee the planet to give warnings to the outside world, but I am not sure.

  • VTC: This is a duplicate of at least one other question on SFF.SE about The Legacy of Heorot.
    – Lexible
    Feb 3, 2022 at 17:14
  • 1
    When I posted my question, I checked the list of questions suggested by the site to see whether it had been asked before, and I did not see it. But, yes, it is the same answer.
    – Alfred
    Feb 3, 2022 at 17:36
  • No worries, Alfred! Closed as a duplicate is not any kind of misstep on SFF.SE: the site's policy is that when a specific work answers more than one question all but one are closed as dupes, and point to a "canonical" answer. You wrote a good question, and I upvoted it!
    – Lexible
    Feb 4, 2022 at 4:33

1 Answer 1


"Legacy of Heorot" by Larry Niven and Jerry Pournelle. Check out the sequel "Beowulf's Children," also good.

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    Welcome to SFF! This is a good find and appears to be correct for what the OP was looking for. However, here we generally try to flesh out answers a bit more and explain how they match the description given in the question. Can you edit your answer to do so here?
    – TheLethalCarrot
    Feb 3, 2022 at 10:12
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    To be fair, @TheLethalCarrot , it is a perfect match to the question, except for the very last line! Going into details could feel a little redundant in this case! :-) (but, yes, I agree that in general a bit more flesh on the answer wouldn't hurt)
    – AdamT
    Feb 3, 2022 at 16:25
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    @AdamT Only if the users recognise the title, remember the plot or go searching for extra info off site. It's always best to make answers as complete as possible even if it is essentially a perfect match and we should encourage such behaviour.
    – TheLethalCarrot
    Feb 3, 2022 at 16:31
  • @TheLethalCarrot I checked on Wikipedia and everything there fit my memories. Also it reminded me of the reference to Beowulf which I had forgotten but came back to me as obvious when I read about it.
    – Alfred
    Feb 3, 2022 at 22:34
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    @AdamT The last line of my question was just a supposition, I did say I did not really remember the end. So it was really a perfect match, confirmed by a rapid check on Wikipedia
    – Alfred
    Feb 3, 2022 at 22:35

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