Formal pond
The form we give our pond when designing it, usually has something to do with personal taste.
However, also with the design of the remaining part of the garden. In a square garden, which is fenced for example by fences or brick walls, a formal pond will be done full justice to. You can consider a stark pond as a continuation of your living room. A stark pond with strong sightlines often is the centre of a garden.
Water plants in a formal pond
You probably also want plants in your je formal pond. In principle every pond plant is suitable for a stark pond. You should reckon, however, with the depth at which different plants should stand. The best thing is to opt for many similar kinds of pond plants together. This provides a quiet picture and it will accentuate the formal form of the pond.
A koi pond usually also is a formal pond. This form is most suitable for keeping koi, the more so because, owing to the square shapes you can enter the depth directly. In this way you can make a deep pond, whereas there is relatively little loss of surface of shallow water. Koi need a pond of at least 60 inches depth to hibernate.