Concrete troughs will hold water.
The newly formed troughs would need to be scrubbed clean to remove surface chemicals inherently found in fresh batched and set concrete, ie, chlorides, sulphates, salts etc that would be detrimental to any plant life or fish you might be considering adding to the finished product.
To minimise freeze thaw damage to the concrete troughs consider using polypropolene fibres and air entrainment admixture to your batching process, this will prevent the concrete cracking or flaking during the colder months.
I would recommend waiting until the concrete has fully cured (28 days) before adding any water, plants or fish.