The Dutch were among the first to become interested in planted aquariums, growing plants successfully since at least the 1940s. The NBAT, the Dutch Aquarium Society, began to host annual competitions with certain guidelines on how tanks were supposed to look like. With the implementation of a set of rules, contestants began to style their tanks accordingly. A style began to take shape.
A Dutch layout from the 1980s.
The hallmark of this style is the tight, manicured look of the bunch plants. Plants are neatly organized into rows which gain height from front to back. Ideally, up to three kinds of plants are used per foot of the aquarium so a four foot tank (48 inches) should ideally have no more than twelve species. Stem plants are carefully chosen for their growth rates as well so as to keep the shape of the 'streets' as low maintenance as possible --hence the use of lobelia and Saururus cernuus is very popular.
Plants should be organized so as to provide maximum contrast in color and leaf shape/size with their neighbors. Colors can include light green, dark greens, browns, reds, pinks, and purples. Small leaved Hemianthus micranthemoides vs large leaved sword plants, round Bacopa caroliniana leaves vs the slender leaves of Ammania gracilis, etc. These neatly organized plants should be arranged and built around the focal point(s) of the tank. Aquariums should have no more than two focal points, usually placed 1/3rd or 2/3rds the length of the tank (rule of thirds).
A Dutch layout from 2001-2002.
Some important considerations are that features in the back of the tank should never catch the eye (no red plants in the back) so as to provide more depth. Also, the tank is usually viewable only from one side. The back wall and sides should be concealed and look as natural as possible, usually with the use of mosses and java fern. They created the first moss walls. Another consideration is that the variety of decoration used should be as minimal as possible, similar to what Amano advocates. Don't use various kinds of rocks or various kinds of wood in a tank --stick to one kind only.
Typical plant choices:
Hygrophila corymbosa v stricta
Fish play a very important part in this style as well. The bottom, middle, and top zones of a tank should be filled with fish to make each area interesting to the viewer. All fish species should be different in shape, color, and size, but the least number of species possible should be used to fill all niches in the tank (so no blue rams in a tank with kribensis, or silver hatchetfish with marbled hatchetfish, etc). A group of larger fish such as angelfish or congo tetras is always appreciated. Schools must be as large as possible.
The appearance of the aquarium in a living room was also critical, usually having the aquarium as being the main piece of decoration. Custom cabinetry incorporating the aquarium into the wall is very popular due to the small size of the rooms. A metal stand or any hardware showing in the living room would be unthinkable.
Lastly, typical technical specs of a Dutch Aquarium:
Tank sizes range from 90 gallons to 300 gallons
Lighting: 1.8 wpg to 2.0 wpg, kelvin ratings are very low (5000k seems to be the norm)
Nitrate tends to be above 10 ppm
Phosphates tend to be low (near zero)
Plant species choice ranges from 12-19
Fish species selection ranges from 5-7