Natural Aquarium Ecosystems — Integrating Classical Ecological Theories in Modern Planted Tank Designs

It is of my well-educated opinion that the development of natural aquariums and its methods represent a fascinating convergence of fundamental ecological theories that emerged from pioneering research in the late 19th and mid-20th centuries. Eugene Odum’s influential theory of ecological succession, articulated in his seminal work “The Strategy of Ecosystem Development” (1969), provides the theoretical foundation for understanding how planted tank communities evolve from simple, unstable assemblages dominated by pioneer species into complex, self-regulating ecosystems. Odum beautifully defined succession as “an orderly process of community development that is reasonably directional and, therefore, predictable” that it “results from modification of the physical environment by the community" and ”culminates in a stabilized ecosystem in which maximum biomass and symbiotic function between organisms are maintained per unit of available energy flow”. This progression mirrors terrestrial succession, beginning with opportunistic colonizers like algae and bacteria that modify water chemistry conditions, followed by the establishment of rooted aquatic plants, and eventually reaching a climax community state characterized by efficient nutrient cycling and stable trophic relationships. I believe that my application of succession theory to aquarium systems reveals how these enclosed environments naturally progress toward greater complexity and stability when ecological principles are reasonably and properly applied.

The foundational work of Raymond Lindeman at Cedar Bog Lake, Minnesota, published in his 1942 paper “The Trophic-Dynamic Aspect of Ecology,” revolutionized understanding of energy flow in aquatic ecosystems providing crucial insights for the overall natural aquarium design. Lindeman’s detailed five-year study of this small, senescent lake demonstrated how energy moves through trophic levels with measurable efficiency rates, establishing the quantitative framework for understanding ecosystem energetics. His work revealed that approximately 10% of energy transfers between successive trophic levels, with the remainder lost to respiration, metabolic processes, and detritus formation. Lindeman’s emphasis on the importance of detritus as both an energy sink and source fundamentally changed ecological thinking, showing how decomposing organic matter supports complex food webs through bacterial decomposition and serves as a critical component in nutrient cycling. In planted tank systems, I believe that this principle manifests in the use of organic substrates and leaf litter, together with the development of mulm, that create foundation food webs capable of supporting diverse microfaunal communities and critical nutrient reservoirs, which in turn provide natural food sources for fish, plants and invertebrates. For instance, the “Father Fish” method of aquarium setup (while limited in aspects of system longevity in my opinion and observations) explicitly incorporates Lindeman’s insights by establishing detrital pathways that support entire ecosystems through natural foraging rather than artificial feeding.

George Evelyn Hutchinson’s groundbreaking niche theory, developed from his observations of water bug coexistence in a small Sicilian pool and published in his celebrated 1959 paper “Homage to Santa Rosalia,” provides some conceptual framework for understanding species diversity and coexistence in confined aquarium spaces. Hutchinson’s revolutionary concept of the ecological niche as an “n-dimensional hypervolume” where environmental conditions and resources define the requirements for a species to persist fundamentally changed how ecologists understood biodiversity patterns. His distinction between the “fundamental niche” (the full range of conditions where a species could theoretically survive) and the “realized niche” (the narrower range actually occupied due to interspecific competition) explains how multiple species can coexist within the limited space of an aquarium through resource partitioning and habitat stratification. Therefore, one can conclude that natural aquarium systems achieve stability through the establishment of diverse microhabitats that support different ecological niches, from benthic decomposer communities in the substrate to epiphytic communities on plant surfaces and planktonic organisms in the water column. The Walstad method (in which system longevity, in my opinion and observations, is also questionable) exemplifies this approach by creating stratified environments where soil substrates support anaerobic bacterial communities, while the overlying water column maintains aerobic conditions suitable for plants and fish, allowing functionally similar species to coexist through niche differentiation.

Stephen Forbes’s prescient yet astonishing 1887 paper “The Lake as a Microcosm” established the conceptual foundation for understanding aquatic systems as self-contained, interconnected communities that would later inspire the intriguing island biogeography theory. Forbes starts his work with an excellent viewpoint that “one finds in a single body of water a far more complete and independent equilibrium of organic life and activity than on any equal body of land.” He then follows up by describing lakes as “a little world within itself—a microcosm within which all the elemental forces are at work and the play of life goes on in full, but on so small a scale as to bring it easily within the mental grasp.” His concept emphasized the remarkable isolation and internal connectivity of aquatic communities, noting that “whatever affects any species belonging to it, must speedily have its influence of some sort upon the whole assemblage”. This insight into the sensitivity and interconnectedness of aquatic ecosystems provides the theoretical yet controversial justification for viewing aquariums as complete, functional ecosystems rather than mere collections of organisms. Forbes’s microcosm concept directly influenced the development of island biogeography theory by Edward Wilson and Robert MacArthur in 1967, which proposed that species diversity on islands reaches a dynamic equilibrium between immigration and extinction rates determined by area and isolation. Perhaps, the island biogeography framework applies directly to aquarium systems, where the tank volume represents area and the degree of external input represents connectivity to source populations. Small aquarium systems, like small islands, support fewer species but can achieve remarkable stability through specialized community interactions and efficient resource utilization.

The synthesis of these classical ecological theories provides a comprehensive framework for understanding and designing natural aquarium ecosystems that function almost as true microcosms. The nitrogen cycle serves as the primary biogeochemical foundation, with Nitrosomonas and Nitrobacter bacteria converting toxic ammonia through sequential transformations while aquatic plants assume increasingly dominant roles in nitrogen uptake as systems mature. Energy flow patterns follow Lindeman’s trophic dynamics, with approximately 10% efficiency in energy transfer between levels and significant energy cycling through detrital pathways that support complex food webs. Hutchinson’s niche theory explains how biodiversity is maintained through resource partitioning, with different species occupying distinct microhabitats and temporal niches that reduce competition. Forbes’s microcosm concept provides the overarching perspective that views these systems as integrated wholes where perturbations to any component cascade throughout the entire community. When properly designed using these ecological principles, natural aquariums can achieve remarkable self-sufficiency, developing stable communities that mirror the complexity and functionality of natural aquatic ecosystems while requiring minimal external inputs for maintenance. The success of low-tech planted systems demonstrates that ecological theory, when thoughtfully applied, can create captive environments that operate according to the same fundamental principles governing natural systems, achieving what Odum described as “maximum protection” strategies where energy allocation shifts from rapid colonization toward maintenance of complex biomass structures and efficient resource utilization.

Even though it has been heavily inspired by those works, the SLESS methodology have also successfully demonstrated ecological patterns according to the classical ecological theory described by these authors. One significant area not addressed in the article, but which SLESS will offer to aquarium ecology, is the use of high CEC (Cation Exchange Capacity) substrates for a more efficient and gradual transition of nutrients from water to soil and, ultimately, to plants. High CEC substrates act as nutrient reservoirs, absorbing and holding essential positively charged ions – such as iron, potassium, calcium, and magnesium – making them readily available to plant roots as needed. This process ensures another consistent and sustained supply of nutrient for aquatic plants, reducing the risk of rapid nutrient depletion or harmful spikes in the water column. Moreover, high CEC substrates support beneficial bacterial communities crucial for breaking down organic matter and further converting stored nutrients into forms that can be easily absorbed by plants. This promotes a dynamic interplay between the substrate, the water column, and plant roots, enhancing the overall resilience, stability, and ecological function of natural aquariums. The gradual nutrient cycling enabled by high CEC materials helps mimic natural aquatic environments, aligning well with the self-sustaining ecological goals of SLESS.

This is only a fraction of what the Litho-Ecological term encompasses within the Symbiotic Litho–Ecological Substrate System (SLESS) method; the full scope of the philosophy, methodology, and supporting data is yet to be presented and discussed here in detail. The true richness of SLESS lies not just in its technical aspects but in a holistic worldview that values the interplay of substrate, life, and natural processes in aquatic environments, drawing inspiration from nature to develop thriving systems with minimal intervention. Future studies will articulate the unique innovations, practical steps, and empirical evidence that define SLESS as a forward-thinking approach in aquarium ecology.

During the early stages of my experience, I maintained several aquariums that followed this conventional model: a 20-gallon long tank for Apistogramma and green fire tetras, and a 10-gallon tall aquarium that housed larger rooted plants alongside burrowing species like zigzag eels and dojo loaches. These systems were biologically rich and productive— Apistogramma bred regularly, plants grew vigorously—but only under strict, sustained management. Despite using commercial “nutrient-rich” substrates, I found myself continuously supplementing with fertilizers, feeding schedules, hardware cleaning, and pest control routines to preserve stability.

This dependency revealed a systemic flaw: the ecological balance in these aquariums was externally sustained rather than internally generated. I began seeking a method that could reduce or eliminate such dependencies by fostering an ecosystem capable of self-regulation. This transition began with the creation of a nano cube—a small-scale aquarium housing shrimp—during a period when financial constraints limited access to commercial aquarium products. Materials such as volcanic ash, laterite clay, and lava rock—available through specialized aquascaping suppliers—presented an opportunity to rethink substrate architecture from a biological and mineralogical standpoint.

What emerged was not a conventional planted tank, but a self-sustaining, open-loop microbial-symbiotic nutrient cycle contained within a compact glass enclosure. I later termed this system the Symbiotic Litho–Ecological Substrate System (SLESS). Unlike my previous setups, the nano cube required no feeding, no fertilization, no regular water changes, and no hardware maintenance. Its only upkeep was the periodic topping off of evaporated water using distilled water—typically once per month. I was fascinated.

Most notably, the system evolved organically over time. Rather than reactively adjusting variables to control biological outcomes, I observed the aquarium mature and adapt under its own ecological momentum. The distinction was profound: in my earlier systems, change was imposed by human intervention; in SLESS, change occurred through ecological succession. This marked the beginning of a methodology grounded not in technological optimization, but in the harnessing of microbial networks, mineral substrates, and biological synergy to sustain life indefinitely.