By Natasha Khardina
Presenting the top winners of the 7th edition of the Biotope Aquarium Contest (BAC2026), organized by the BIOTOPE AQUARIUM Project (BAP), an independent educational project that aims at motivating aquarists to study the surrounding aquatic environments by applying their knowledge in the recreation of biotope aquariums.
An aquarium can be much more than a beautiful representation of an underwater landscape. It can become a way to discover a real place in nature.
This is the idea at the heart of the BIOTOPE AQUARIUM Contest.
Unlike an aquarium created primarily as an artistic composition, a biotope aquarium begins with a real geographical location. The aquarist chooses a river, lake, stream, floodplain or another aquatic habitat and tries to understand what makes that particular place unique.
Where is it located?
What are the characteristics of its water?
What does the bottom look like?
Which plants and animals live there?
How do they interact with their environment?
And how does the habitat change during the year?
The aquarium comes afterwards.
Nature is the starting point.
This simple difference changes the entire process. Creating a biotope aquarium requires research, observation and documentation before the first stone, branch or plant is placed in the tank.
The aquarist becomes an observer.
Nature is the starting point.
This simple difference changes the entire process. Creating a biotope aquarium requires research, observation and documentation before the first stone, branch or plant is placed in the tank.
The aquarist becomes an observer.
Sometimes the information comes from scientific publications, museum collections, biodiversity databases and field studies. Sometimes it begins with a personal visit to a river or lake, photographs taken in the field, conversations with local researchers or observations made during years of keeping a particular species.
All these pieces of information help transform an aquarium into a documented reconstruction of a real aquatic environment.
From aquarium keeping to Citizen Science
This is also where the BIOTOPE AQUARIUM Contest meets Citizen Science.
Citizen Science creates opportunities for people outside professional research institutions to participate in the observation and documentation of the natural world. In the BAC, aquarists contribute by investigating aquatic habitats, collecting information, identifying species, documenting locations and sharing their findings with others.
The result is not intended to replace scientific research.
Instead, it creates another bridge between scientific knowledge and the public.
An aquarist who researches the natural habitat of a fish may discover that the species occurs only in a particular river system. Another may learn that a familiar aquarium plant has a very different role in nature from the one it has in a conventional aquarium. Someone else may discover a small stream, lake or endemic species that was previously completely unknown to them.
The aquarium becomes the starting point for questions.
And questions lead to discovery.
Through the BIOTOPE AQUARIUM Project (BAP), documented information about natural habitats can also be connected with geographical locations, photographs, species data and field observations through the BAP Map.
In this way, the work of individual aquarists can become part of a much larger picture: a growing collection of documented aquatic biotopes from different parts of the world.
Recognising the work behind the aquarium
As this approach develops, another important aspect is emerging: the value of the knowledge and work accumulated by the aquarist.
A carefully researched biotope aquarium involves skills that go far beyond aquarium maintenance. It requires the ability to find and evaluate information, observe natural environments, identify organisms, document sources, understand ecological relationships and communicate what has been discovered.
The BAP Certification initiative is being developed to recognise this process and the knowledge acquired through documented BIOTOPE AQUARIUM activities.
The purpose is not simply to certify an aquarium.
It is to recognise the learning, research, observation and documentation behind it.
For experienced aquarists, this provides a way to give structure and recognition to knowledge acquired through years of exploration and study. For younger aquarists and students, it can offer an introduction to scientific observation and environmental education.
And for the aquarium community as a whole, it demonstrates how a hobby can become a meaningful connection between people and aquatic biodiversity.
The BAC2026 journey
This year, the 7th edition of the BIOTOPE AQUARIUM Contest once again brings together aquarists from around the world.
Their aquariums represent eight geographical regions and an extraordinary variety of aquatic habitats. Some recreate clear, fast-flowing mountain streams; others represent quiet floodplains, river margins, forest waters or shallow lake habitats. Some focus on well-known aquarium species, while others introduce fish and plants that are rarely seen in the hobby.
What unites them is not a particular aquarium style.
It is the connection to a real place in nature.
The BAC is therefore not simply a competition between aquariums. It is also a collection of stories about rivers, lakes, species and ecosystems – researched and documented by aquarists and shared with an international community.
This is what makes every edition different.
Every year, new habitats are discovered. New species attract attention. New observations are documented. And new aquarists become involved in the process.
We do not start with the aquarium and search for a story afterwards. We start with nature and bring the story into the aquarium.
Here are the winners of BAC2026 and the natural habitats they chose to recreate.
NORTH AMERICA
Sponsored by FLUVAL
Approved by: Fritz Rohde, Lawrence Kent and John T. Baxter
DUCK CREEK QUARRY, HOWARD, WISCONSIN
By Luke Manty
“This 254L biotope is a recreation of the unique underwater landscape that fascinated me while growing up. The goal was to create a limestone cliff overlooking a garden of aquatic plants, submerged wood, and organic substrate. Multiple pieces of limestone were carefully arranged to form the central structure. To reflect the natural schooling behaviour of the fish, the upper half of the aquarium is left relatively open. A large piece of wood was positioned upright and partially buried in the substrate. The fish actively school around its branches, especially during feeding.
To recreate the dense underwater vegetation, several plant species, including hornwort (Ceratophyllum demersum) and duckweed (Lemnoideae), were collected and planted in the substrate. Decayed leaves and waterlogged branches were scattered across the bottom.
The aquarium is inhabited by a pair of Rock Bass (Ambloplites rupestris), ten juvenile Bluegill (Lepomis macrochirus), and one Johnny Darter (Etheostoma nigrum).
The vegetation consists of duckweed (Lemnoideae), hornwort (Ceratophyllum demersum), water milfoil (Myriophyllum spp.), and American eelgrass (Vallisneria americana). As the quarry temperature naturally varies with depth, the aquarium is maintained at room temperature (20°C/68°F).”
CENTRAL AMERICA & CARIBBEAN
Sponsored by BIOTOPE AQUARIUM Project
Approved by: Michael Köck & Jairo Arroyave
LAGUNA EL ARCO, OCOYOACAC, MÉXICO
By Amadeo Hernández Pérez
“The main inhabitant represented in this project is the Moctezuma Frog (Lithobates moctezumae) in its larval stage. This amphibian is endemic to Mexico and is listed under NOM-059-SEMARNAT-2025 as a species subject to special protection.
The recreated biotope area is characterised by abundant rooted emergent aquatic vegetation, mainly Eleocharis palustris, which provides shelter for Lithobates moctezumae individuals against human disturbance. The larvae develop primarily on the soft substrate that characterises this habitat.
To faithfully recreate this biotope aquarium, all natural elements were collected responsibly, with the aim of maintaining the ecological characteristics of the original environment.”
SOUTH AMERICA
Sponsored by SICCE
Approved by: Roberto E. Reis, Pablo C. Lehmann & Antonio Machado-Allison
IGAPÒ, LAGO MAQUI, RIO DEMINI, AMAZONAS, BRAZIL
By Asier Murga Arteta
“This aquarium depicts a flooded forest on the Rio Demini, inspired by a YouTube video that struck me with its natural beauty.
I chose a small group of three Apistogramma bitaeniata (Brazil wild) (one male and two females), as they are the closest relatives of A. paucisquamis and A. mendezi. Not only are they beautiful, but they show a very unusual pattern on the caudal fin, a well-known characteristic in all three species. It is the Apistogramma most similar to those found in the captures and in the YouTube video of the Rio Demini igapó that I could find in the ornamental fish market. I chose to keep them wild to maintain the purest possible lineage, without human intervention. It was a wonderful challenge to acclimatise them to life in an aquarium.
Their companions are a colourful group of fifteen Paracheirodon axelrodi, which, in the right biotope conditions, display a truly striking blue neon and red coloration.
The composition reproduces a submerged landscape during the seasonal flood.”
EUROPE
Sponsored by DOHSE AQUARISTIK
Approved by: Markku Varjo, Francesco Denitto & Alexey Malyshev
ORCIA RIVER, CASTIGLIONE D’ORCIA, SIENA, TUSCANY, ITALY
By Pawel Lukasz Kocik
“This aquarium is a faithful reproduction of the Orcia River ecosystem in its Tuscan hillside stretch, right at the foot of Castiglione d’Orcia. The choice stems from a desire to recreate a unique Mediterranean river environment, characterized by strong seasonal variations, and to showcase our local biodiversity, which is often overshadowed by classic tropical biotopes.
The layout is inspired by the striking limestone gorges of the Val d’Orcia. The substrate consists of a mix of fine sand and rounded river pebbles of various sizes, arranged to simulate the force of the water current. Smooth, water-worn driftwood pieces complete the hardscape.
The most interesting feature is the dynamism of the setup: intense lighting stimulates the growth of an algal biofilm on the rocks, which is essential for grazing bentic fauna, while a well-directed current keeps the water highly oxygenated. A true fragment of wild, fascinating Tuscany, enclosed within a tank.”
AFRICA
Sponsored by AQUAEL
Approved by: Ad Konings & Anton Lamboj
CLEARWATER FOREST CREEK, SOUTHERN PROVINCE, SIERRA LEONE
By Kishalay Das
“This 140-litre aquarium recreates a quiet forest creek in Sierra Leone’s Southern Province. A substrate of fine white sand is complemented by driftwood, cocopeat, decomposed leaf litter, and fallen palm leaves, reproducing the organic-rich environment found beneath the dense rainforest canopy. Nymphaea lotus serves as the focal aquatic plant, reflecting the characteristic vegetation of this habitat. Observing its first flower bloom in the aquarium was one of the most memorable and rewarding moments of the project.
The fish community, consisting of Poropanchax normani and Epiplatys annulatus, represents species adapted to calm, shallow forest waters where submerged wood and leaf litter provide shelter, foraging opportunities, and spawning sites. The aquarium aims to faithfully capture the simplicity, tranquillity, and ecological character of a West African forest creek while remaining as true as possible to the natural habitat.”
EASTERN ASIA
Sponsored by NIXO
Approved by: Sun Kai, Zhou Hang & Wei-Cheng Jhuang
LOTUS MOUNTAIN STREAM, SHANWEI, GUANGDONG, CHINA
By Yunfei Long
“This 54L biotope aquarium recreates a microhabitat from a Lotus Mountain stream in Guangdong, representing a submerged slope along the stream margin during the dry season.
The inspiration came from observations of Rhinogobius zhoui, where tangled twigs, leaves, and accumulated organic sediment were found within underwater crevices. After visiting the site and studying the dry-season sediment deposits, all materials used in the aquarium were responsibly collected from the native stream environment.
Flow-transported boulders create natural gaps and shelters, while layers of gravel, leaf litter, twigs, and fine sediment accumulate within these spaces. The arrangement of coarse rock and soft sediment, combined with scattered submerged branches, recreates the complex structure and natural appearance of the stream habitat.
All inhabitants originate from the same ecosystem: Rhinogobius zhoui uses the spaces beneath stones for shelter; Pseudogastromyzon laticeps grazes algae from rock surfaces; Macropodus hongkongensis hides among submerged branches and emerges rapidly to capture prey; and Sulcospira hainanensis forages slowly across the substrate.
This aquarium condenses the microtopography of the stream into a small volume while demonstrating behavioural niche differentiation among coexisting species. Through this biotope, I hope to share the beauty and ecological value of China’s freshwater ecosystems with a wider audience.”
SOUTHERN, CENTRAL & WESTERN ASIA
Sponsored by JBL
Approved by: Hans-Georg Evers & Friedrich Bitter
CHALIYAR RIVER, WESTERN GHATS, KERALA, INDIA
By Juhász-Tóth Gábor
“My favourite freshwater fishes are barbs, so I created an aquarium featuring several larger species such as Dawkinsia filamentosa and Sahyadria denisonii. The aim is to recreate a fast-flowing forest stream with marginal vegetation.
So I used large rocks to represent the riverbank, with marginal vegetation, and smaller rocks over a gravel substrate across the bottom of the aquarium. Catappa leaves and smooth driftwood were added to create natural details.”
SOUTHEASTERN ASIA & OCEANIA
Sponsored by BIOTOPE AQUARIUM Project
Approved by: Heok Hee Ng & Greg Martin
DON CAT STREAM, PHONG THAI DISTRICT, VIETNAM
By Điền Lương Nguyễn Quốc
“The aquarium recreates a middle reach of Don Cat Stream, Phong Thai District, Vietnam, during the post-flood period, when water levels begin to recede, currents slow down, and the ecosystem gradually returns to stability.
The design is inspired by decaying tree trunks, submerged branches, and layers of accumulated leaf litter covering the streambed – traces left behind by powerful floodwaters. Although the scenery reflects the dynamic forces of recent flooding, it also reveals a natural balance, where the current has diminished and the habitat has transitioned into a calmer, deeper, and life-filled environment.”
The aquarium recreates a middle reach of Don Cat Stream, Phong Thai District, Vietnam, during the post-flood period, when water levels begin to recede, currents slow down, and the ecosystem gradually returns to stability.
The design is inspired by decaying tree trunks, submerged branches, and layers of accumulated leaf litter covering the streambed – traces left behind by powerful floodwaters. Although the scenery reflects the dynamic forces of recent flooding, it also reveals a natural balance, where the current has diminished and the habitat has transitioned into a calmer, deeper, and life-filled environment.
The real value of a biotope aquarium does not end when the competition is over.
The research remains.
The photographs remain.
The observations remain.
The knowledge can be shared.
And perhaps, somewhere, another aquarist will see one of these aquariums and ask a simple question:
Where is this place in nature?
That question is where the next journey begins.
Explore. Create. Discover.
The international aquatic companies Aquael, Fluval, JBL, Nixo, Sicce and Dohse Aquaristik understand how important it is for the aquatic hobby to evolve. They look forward to a positive change and embrace the biotope concept as a top level of the aquarium hobby.
Sponsored by
