Flooded area on the Krężniczanka river, near Bełżyce, Poland

_ place in Biotope Aquarium Design Contest 2019

Volume: 54 L
Dimensions: 60x30x30 cm
List of fishes: Gasterosteus aculeatus, Planorbis planorbis, Lymnaea stagnalis,
List of plants: Ceratophyllum demersum, Elodea canadiensis
Description of decorations: Elements of decoration came from the river. Sand, mud, deadwood, roots and reeds.
Description of equipment: Filtration: Aquael FZN 3 1200l/h, Lighting: 10W LED 8000k
Water parameters: Water temperature is 20-22°C, hardness is 20dH and the pH is 7.5
Additional info: Water change ones a week 20%, Reeds are changed every 6-8 months.

INFORMATION ABOUT BIOTOPE

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 20dH, pH is 7.5. Temperature in summer is 23-28°C, in winter the place 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:
https://pl.wikipedia.org/wiki/Ciemi%C4%99ga_(po%C5%82udniowy_dop%C5%82yw_Bystrz
My observations:
https://www.explorebiotope.com/italy-copy-1

Comments of the members of the jury of Biotope Aquarium Design Contest 2019