Flooded area on the Krężniczanka river, near Bełżyce, Poland

22nd place in Biotope Aquarium Design Contest 2018

russia Poland. Bartłomiej Paśnik

Volume: 150 L
Dimensions: 100x50x30 cm
List of fishes: Gasterosteus aculeatus, Pseudorasbora parva, Lymnaea stagnalis, Radix sp., Nepa cinerea, Stagnicola palustris
List of plants: Callitriche palustris, Veronica sp.
Description of decorations: Elements of decoration came from the river. Sand, mud, deadwood, roots and reeds.
Description of equipment: Aquael FZN 3, Led 30W 6000k
Water parameters: Water temperature is 20-22°C, hardness is 15dH and the pH is 7.0


Description of the area surrounding the biotope:  The river in Lublin Voivodeship, which is the left tributary of the Bystrzyca river. It flows between the villages Zagórze and Krężnica. Then take a turn and heads east to the city of Bełżyce, in the village of Babin begins to meander strongly and help to create picturesque landscapes. The river is over 20km long and ends its course near Lublin, affecting the marshy area to the Bystrzyca river. Presented flooded area are the result of the beavers’ activities, they are surrounded by meadows, reed beds and fallen trees.

Description of the underwater landscape of the biotope: The bottom is covered with mud, and a small amount of plants and dead wood, creating excellent great environment for breeding fish. The only species I’ve seen is Gasterosteus aculeatus and Pseudorasbora parva, it is an invasive species and comes from Asia. For several years, permanently settled in Polish waters. The depth is small, about 20-50 cm, and the water temperature in the summer reaches even 28°C.

Description of the parameters of the habitat: Turbid water, hardness about 15dH, pH is 7.0. Temperature in summer is 23-28°C, in winter the tank completely freezes.

List of fishes and invertebrates occurring in the nature biotope: Gasterosteus aculeatus, Pseudorasbora parva, Gobio gobio, Perca fluviatilis, Salmo trutta, Thymallus thymallus, Rutilus rutilus.

List of plants found in the nature biotope: Sagittaria sagittifolia, Ceratophyllum demersum, Elodea canadiensis, Berula erecta, Callitriche palustris.

Threats to the ecology: The river was severely polluted in the 1980s and 1990s, leading to the complete extinction of Astacus astacus and Pseudanodonta complanata. Unfortunately, all the time Krezniczanka is exposed to the negative impact caused by humans,  littering or flushed fertilizers from nearby fields negatively affect this small ecosystem.

Sources of information:

Comments of the members of the jury of Biotope Aquarium Design Contest 2018

Here, I again dive with a mask and a tube among the thickets of reeds. Very realistic entry with species of fish and shellfish common in Europe, which also deserve to be represented at the competition along with rare tropical fish.

Alexey Malyshev

You want a biotope aquarium which looks like a real biotope, well, here it is. As I stare at it, I am subconsciously waiting for more fish to swim up the river and come out from behind the reeds. Vertical reeds are not easy to pull off and make them look natural. Bartłomiej Paśnik did an amazing job here, congratulations! The leaves and wood are placed just so, as they should be. The whole scenario is a great tribute to nature.

Ivan Mikolji

Interesting work. Good job. For me the plants could have been arranged “wilder”, but this is a nice biotope. But keep refreshing the reeds regularly, but I assume that you know this.

Jeroen Vanhooren