Flooded area on the Krężniczanka river, near Bełżyce, Poland

3rd place in Biotope Aquarium Design Contest 2019

Poland. Bartłomiej Paśnik

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.


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:
My observations:

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

An excellent selection of fish and decoration contributes to the appearance of a larger aquarium. It is important to align these two elements to make the fish feel comfortable and to keep the aquarium nice for the eye. Although it contributes to natural appearance, the only questionable part is the reed, which will eventually rot and will need to be changed.

Petra Bašić

Ah, Sticklebacks and snails — the first ‘biotope’ experience for many a UK kid with a net and a jar. These inhabitants are bulletproof and it would be hard to set up something bad for them. But give them the delicious reed-based layout they have here, along with ample hiding places, and you have an exceptional species. It is a shame that the aquarist hadn’t seeded the tank with Gammarus or similar to live along the bottom. With such a bounty of live food, these Sticklebacks would be flame-throated and spawning in no time. But look at those fish as they are — they’re immaculate!

Nathan Hill

When I was child all my holidays I spent in place with similar river. Now I come back to old time and I remembered walking on such a river, fishing. This aquarium is for me the best in this competition. I thinking that I don’t watch the aquarium but I wade in the river. All is perfect. My the best congratulation. Nice that it is polish river and polish participant!

Marta Mierzeńska

A very good designed tank with the right species, just the arrangement of wood and plants could be with a bit more natural look-alike.

Anton Lamboj

Last year, the author submitted a similar biotope with the same fishes. This time there is nothing to complain about: everything is great. This is how it should be: you should study those water bodies that are near your house. Such reservoirs can be studied for years, and you will know more about the life and habits of the inhabitants than the coolest scientists.

Alexey Malyshev

It is a very interesting work where the arrangement of the materials makes an impression of quite real depth. The driftwood looks very natural in the layout. Well done, congratulations!

Víctor Ortiz