Hi,

i can't get the fish to lay the eggs on the second task because the fish requires (according to the Breeding Icon) a vertical spot but it is not available in the scenario. The task indicates that a horizontal space is required which is available.

I'm not still there in the campaign, but I see that not all the needed things are immediately available, sometimes you'll have to research something or wait for some other achievement to get what is needed.

It that a main quest or an optional one ?

It is the main task.
In this scenario there are no visitors (science camp) - so no research.
I think the fish requirement was changed later on but the campaign was not tested.

I did the task, you need to put a plain rock in the tank