Addressing Sustainability Challenges in the Global Aquarium Wood Market

Abstract

The aquarium trade includes a niche but significant market for ornamental wood, yet its sustainability remains largely unexamined. This study combines traditional wood anatomical methods with conservation assessments to investigate the sustainability of this overlooked sector. We investigated the botanical identity of aquarium wood products to assess mislabelling, conservation concerns, and potential environmental risks. Using macroscopic and microscopic wood anatomy techniques, we analysed wood samples from the aquarium trade to determine taxonomic identity. We also examined the origin, conservation status, and possible ecological implications of the identified taxa. We identified woods from diverse families, including Myrtaceae, Ericaceae, Fabaceae, and Ebenaceae, with some species listed as threatened. Widespread mislabelling obscures conservation status, enabling unsustainable trade. Moreover, several samples were identified as roots, raising concerns about soil disruption and habitat degradation. By linking wood anatomy and ecosystem impacts, we show that the aquarium wood trade lacks transparency, posing risks to biodiversity conservation and ecosystem stability. Our findings underscore the pressing need for effective regulatory oversight, accurate labelling, and sustainable sourcing to mitigate environmental impacts and promote responsible trade practices.

1. Introduction

The aquarium industry represents a significant global market, providing hobbyists with ornamental fish, corals, invertebrates, and other elements essential for creating vibrant aquatic ecosystems [1]. Annually, 14–30 million fish from over 1800 species, 1.5 million live stony corals, and 9–10 million other invertebrates are traded globally [2,3]. Much of this trade originates from the wild catch of ornamental organisms in coral reefs, with Indonesia and the Philippines supplying over two-thirds of these [4]. The United States, the European Union, and Japan are the largest importers [5], highlighting the economic importance of the industry [6,7] and its role in connecting biodiversity hotspots with international markets [8].

Aquarium wood, marketed under names such as “mangrove wood”, “spider wood”, “mopani wood”, and “driftwood”, plays a niche yet significant role in the aquarium trade. These decorative wooden pieces, often including twisted and gnarled stems, branches, and roots, are highly valued for their aesthetic appeal. They are widely used to decorate aquariums, providing hiding places for fish and creating naturalistic underwater landscapes. Prepared by sanding, drying, and sometimes boiling to reduce water discolouration and buoyancy, aquarium woods are in demand in various shapes and colours. While quantitative data on the aquarium wood market remain limited, the apparent demand underscores its economic and ecological relevance.

There is a broad body of research on the ecological issues caused by the trade of marine fish and corals, such as the increased threat of disease and the introduction of invasive species [1,9,10,11,12]. Aquarium wood may also serve as a vector for the transcontinental spread of fungal pathogens [13]. A recent North American study showed that infected decorative wood remained viable in aquariums for several years [14]. The discovery of the same exotic fungus in aquariums from different U.S. states raises concerns that these products could introduce other microorganisms, including plant pathogens [15]. Although these studies used DNA sequencing for fungal identification, the wood species remained unknown. The authors noted that these items often included complex, branched shapes with galls, holes, and crevices, likely originating from degraded tropical woods collected in coastal or forest floor environments in Southeast Asia. However, to our knowledge, no studies have investigated the possible environmental damage caused by the woods used in aquariology.

A list of commonly used aquarium woods was compiled during our online survey of aquarium retailers, where various commercial names were frequently observed despite the lack of verified taxonomic attribution. Here, we verify the botanical attributions of samples purchased from two physical stores and their consistency with label claims, if any. We then discuss the extent and implications of wood misidentification and ambiguous sourcing in the aquarium trade.

2. Material and Methods

Eight aquarium wood samples were bought in October 2024 from two aquarium shops located in Torino (northwestern Italy) (Figure 1a,

Table 1. Identification and characterisation of wood samples collected from aquarium retailers. The table lists the commercial name, identified family/genus/species, plant part (root, root collar, stem, branch, or not applicable), growth habit, distribution range, and habitat for each sample. Results highlight the mislabelling of wood products and their diverse taxonomic origins.

#	Commercial Name	ID (Family/Genus/ Species)	Part of the Plant (Root/Root Collar/Stem/Branch/na)	Habit	Distribution Range	Habitat
1	Driftwood/Koren mangrove	Myrtaceae (cf. Xanthostemon, Syncarpia, Tristaniopsis)	Root	Trees or shrubs	Tropical and subtropical Australia and Southeast Asia	Rainforests, woodlands, and coastal areas
2	-	Ericaceae, Rhododendron sp.	Root and root collar	Shrubs or small trees	Northern Hemisphere, with high diversity in Asia, particularly the Himalayan region, and parts of North America and Europe	Prefers acidic, well-drained soils, commonly found in temperate to subalpine forest ecosystems, high-altitude areas, and moist, shaded environments
3	Mangrove	Myrtaceae (cf. Xanthostemon, Syncarpia, Tristaniopsis)	Stem	Trees or shrubs	Tropical and subtropical Australia and Southeast Asia	Rainforests, woodlands, and coastal areas
4	Mopani	Fabaceae Colophospermum mopane	Stem	Tree or shrub	Southern Africa	Semi-arid areas, typically found in savannas, woodlands, and along riverbanks
5	Honeycomb wood	Myrtaceae, Eucalyptus sp.	Stem or branch	Tree or shrub	Native to Australia, with species also planted in Southeast Asia, the Pacific Islands, and some parts of South America, Africa, and the Mediterranean	Diverse environments, including temperate and tropical forests, grasslands, and arid zones
6	Azalea	Ericaceae, Rhododendron sp.	Root and root collar	Shrubs or small trees	Northern Hemisphere, with high diversity in Asia, particularly the Himalayan region, and parts of North America and Europe	Prefers acidic, well-drained soils, commonly found in temperate to subalpine forest ecosystems, high-altitude areas, and moist, shaded environments
7	Black slim wood	Fabaceae Baikiaea sp.	Root and root collar	Tree or shrub	Native to tropical and subtropical regions of Africa, particularly Southern Africa	Dry woodlands, savannas, and sandy soils, often in areas with low rainfall or semi-arid conditions
8	Spider root kipouss	Ebenaceae, Diospyros sp. (tropical)	Root	Tree or shrub	Tropical to subtropical regions, widely distributed across Asia, Africa, and the Americas	Tropical forests, from lowland rainforests to montane environments, and drier habitats or savanna ecosystems

). The selection was intended to represent the range of wood shapes, colours, and types commonly represented in such shops and therefore used by aquarists. Upon acquisition, each wood sample was coded, photographed, and catalogued to document its appearance and the accompanying labelling information provided by the retailer.

Each sample was initially examined visually and macroscopically to assess key macroscopic wood characteristics, including the visibility and distribution of vessels (conduits that transport water in the plant) and the occurrence and distribution of axial parenchyma and rays (structures that store starch) [16,17]. Then, we analysed the wood samples under a transmitted light microscope to confirm or improve the identification accuracy. To allow microscopic observation, thin wood sections were prepared using standard microtomy techniques and stained with safranin and astrablue to highlight the visibility of anatomical features and cell inclusions [18]. Microscopic analysis focused on collecting anatomical features according to [19]. Anatomical observations were compared with existing standards and materials available on InsideWood [20,21,22]. We collected geographical distribution data for each identified taxa from the Plants of the World database [23].

3. Results

A detailed examination of the collected aquarium wood samples revealed diverse taxa, plant parts, and geographic origins, highlighting significant discrepancies between marketed names and actual botanical identities (Table 1).

A detailed examination of the samples labelled mangrove (Samples 1 and 3, Figure 1a) revealed that they were not true mangrove species (e.g., Rhizophora sp. or Avicennia sp.), as they lacked included phloem, a characteristic anatomical feature of mangrove wood visible to the naked eye. Microscopic analysis revealed that both samples had matching anatomical features (Figure 1b) and belonged to the Myrtaceae family, although a precise genus identification was not possible (Table 1). Sample 4, labelled mopani (Figure 1a), exhibited macroscopic characteristics consistent with Colophospermum mopane, a tree native to Southern Africa. This identification was corroborated by microscopic analysis (Figure 1b). Sample 6, labelled Azalea, and Sample 2, which lacked a label (Figure 1a), were identified as belonging to the genus Rhododendron (Table 1, Figure 1b). The label Azalea was consistent with the taxon, as it is a common term used to describe plants of this genus. The remaining samples (5, 7, and 8) were labelled with fanciful names: “honeycomb wood”, “black slim wood”, and “spider root kipouss”, respectively (Figure 1a). These names could not be linked to specific taxa. The microscopic analysis identified the samples as Eucalyptus (Sample 5), Baikiaea (Sample 7), and Diospyros (Sample 8), representing a wide geographic and ecological range (Table 1, Figure 1b).

4. Discussion

Although precise figures on the global or national trade volume of aquarium wood are not available, the lack of such data is a cause for concern. The trade in aquarium goods, primarily fish, but also marine ornamentals and possibly decorative woods, is better documented in some regions, such as Indonesia [24]. However, as noted by [5], the absence of a dedicated monitoring system for the wildlife aquarium trade severely hampers efforts to track and assess the flow of products, including ornamental wood, which is rarely systematically recorded. Decorative wood products are often grouped under broad categories such as pet accessories in trade databases (e.g., UN Comtrade HS Code 442199), making specific tracking difficult. In Italy, for instance, national statistics (e.g., ISTAT) do not distinguish aquarium wood from other decorative wood or pet supply items. Even vendor websites suggest that “hundreds” of wood pieces are sold, often with no clear information on origin, species, or environmental impact. This opacity obscures the scale and legality of sourcing practices and undermines efforts to evaluate the sustainability of the trade or to enforce regulatory frameworks. Without traceable origin data or formal reporting mechanisms, threatened or mislabelled species may circulate under fanciful commercial names.

The aquarium ornamental wood products identified on the eight samples analysed in this study included plant species thriving in diverse habitats, highlighting aquarium wood’s wide geographical and ecological provenance (Figure 1c). Although limited in number, these samples already revealed a major underlying issue in the market, exposing widespread mislabelling and a lack of transparency. Such results highlight a significant gap in labelling accuracy and species identification within the aquarium industry, raising concerns about transparency and the broader environmental implications of the aquarium wood trade.

The absence of actual mangrove wood in the sampled pieces is indeed a positive finding, given the critical ecological role mangroves play in coastal ecosystems. In fact, mangroves provide essential services such as shoreline stabilisation, carbon sequestration, and habitat for diverse species [25,26]. The unsustainable harvesting of mangrove wood for aquarium use would exacerbate the threats of these ecosystems.

Unfortunately, two of the three possible genera mislabelled as mangroves, Xanthostemon and Tristaniopsis, also raise concerns about sustainability and the potential for illegal trade. According to the IUCN (International Union for Conservation of Nature) Red List of Threatened Species [27], one species of the genus Xanthostemon is near threatened, seven are vulnerable, and four are endangered. One is critically endangered, making twelve species globally threatened with extinction, to which we must add one already extinct species. For Tristaniopsis, out of 18 globally threatened species, 2 are near threatened, 5 are vulnerable, 6 are endangered, and 5 are critically endangered. Notably, logging and wood harvesting are significant threats to Xanthostemon and Tristaniopsis.

There are also serious concerns about other identified taxa. The genus Diospyros contains 274 threatened species out of a total of 779. Of these, 37 (13%) are listed as near threatened, 92 (33%) vulnerable, 105 (38%) endangered, and 40 (14%) critically endangered. Logging and wood harvesting are collectively the second most significant threats to Diospyros and, interestingly, are mainly classified as small-scale exploitation, to which aquarium woods can be linked. The Diospyros species from Madagascar have also been under CITES (Convention on International Trade in Endangered Species) protection since 2013, with an Appendix II listing.

The genus Baikiaea contains an endangered species, Baikiaea ghesquiereana. However, this classification is not due to direct logging but to habitat destruction caused by agriculture and the extraction of Pterocarpus timber.

Of less concern is Colophospermum mopane, which, apart from being one of the only two cases of correctly labelled products, is listed by the IUCN as Least Concern. For Rhododendron, on the other hand, although the label Azalea refers to the correct genus, the absence of the exact species is a cause of concern, as 40 species are globally threatened with extinction, of which 5 are near threatened, 22 are vulnerable, 8 are endangered, 4 are critically endangered, and 1 is extinct in the wild, with logging and wood harvesting being the third most significant threat.

The identification of some aquarium wood pieces as roots (Table 1) raises concerns about the environmental impact of root harvesting. Roots are highly sought after in the aquarium trade because of their intricate shapes. However, their extraction disrupts soil stability, causing erosion, reduced fertility, and the destruction of microhabitats essential for biodiversity and nutrient cycling.

While this study relied on traditional macroscopic and microscopic wood anatomical analysis, we acknowledge that molecular tools such as DNA barcoding may offer valuable support in resolving closely related species or confirming identifications at the species level [28,29]. However, these methods are currently limited by the availability of comprehensive reference databases and are highly dependent on the quality of extracted DNA [30], which is often degraded in dry, treated, or processed wood products such as those traded for aquariums. As such, DNA-based approaches are not yet a reliable or routine solution for identifying commercial ornamental woods. Nevertheless, we recognise the potential of molecular techniques as a complementary tool for future studies aiming to enhance species traceability and authentication in the aquarium wood trade.

The widespread retail availability and taxonomic variety of such products suggest a non-negligible trade volume and highlight the urgent need for improved reporting standards, product traceability, and regulatory oversight, especially in light of the European Union Deforestation Regulation (EUDR 2023/1115) [31], which mandates risk assessment based on species, origin, and supply chain transparency. However, the findings of this study raise significant concerns regarding aquarium wood trade’s sustainability and compliance with the EUDR. The regulation prescribes an assessment of the risk of illegal sourcing based on various criteria, including the country of provenance, the wood species, and the complexity of the supply chain. These considerations are especially relevant for aquarium wood, as it may be sourced from tropical countries with high deforestation rates, come from endangered wood species, and be traded through complex supply chains involving multiple intermediaries [24]. Failure to comply with the EUDR is not only a sustainability issue but also an operational risk for companies, which can be subjected to relevant administrative sanctions, even when the illegal trade is unintentional.

Addressing challenges in aquarium wood trade requires collaboration among stakeholders, including retailers, consumers, regulators, and scientific institutions. Three main policies are recommended.

Firstly, a practical approach is to promote sustainability by using wood from forests certified by sustainable forest management schemes. While developing specific certification schemes for aquarium wood may hold potential, their complexity and market effectiveness would require careful evaluation. Operators and traders should implement due diligence systems to ensure compliance with regulations such as the European Union Deforestation Regulation (EUDR) [31]. Given the critical issues discussed above, it is recommended that risk assessment procedures are implemented with additional measures to strengthen their effectiveness. This may include regular reference to wood identification services to verify the type of wood being traded. From an operational perspective, operators and traders may also strive to establish simple supply chains, as their complexity increases the risk of illicit trade. Beyond meeting legal requirements, such approaches can also be a valuable marketing asset.

Secondly, public awareness must be raised of the environmental and practical consequences of misidentifying aquarium wood products. Educating consumers and aquarists on such issues can drive demand for sustainably sourced and accurately labelled products. Public awareness campaigns, utilising social media, online platforms, and engagement with influential aquarium communities, can effectively amplify this message.

Third, it is essential to foster collaboration between scientists and practitioners in the aquarium and woodworking communities. Strengthened scientific research and dialogue will bridge gaps between knowledge and practice, improving the understanding of the ecological implications of wood use in aquariums. Accessible educational resources, such as identification guides for aquarium wood, would further support these efforts.

5. Conclusions

Misidentifying woods in the aquarium trade poses significant risks to biodiversity, conservation efforts, and consumer trust. This study highlights the critical need for stricter species identification standards and enhanced regulatory oversight to ensure sustainable practices in the global wood trade. By improving transparency and accuracy in labelling, we can mitigate the ecological impacts of misidentified wood species, support conservation initiatives for threatened taxa, and safeguard the health and sustainability of aquatic ecosystems. While our findings offer a valuable initial assessment, a larger and more comprehensive study is needed to provide a sharper, globally representative picture of the extent and dynamics of the aquarium wood trade.