{"topic_id":"evidence_exotic_fish_toxicology","category":"evidence","context":"---\ntopic_id: evidence_exotic_fish_toxicology\ncategory: evidence\ntitle: \"Evidence cluster — Aquarium fish (teleost fish) toxicology (peer-reviewed, Europe PMC)\"\nlang: en\nsource: \"Europe PMC (Europe PubMed Central) REST search, first-hand peer-reviewed abstracts, pulled 2026-08-01\"\nsource_file: pdf-raw/evidence/europepmc_fish_toxicology_2026-08-01.txt\ndate_parsed: 2026-08-01\ntokens_estimated: 4870\nverification:\n  method: paraphrase\n  claims: 11\n  passed: 11\n  date: 2026-08-01\nsource_document: \"Peer-reviewed Aquarium fish toxicology literature (Europe PMC, first-hand abstracts)\"\ncitation:\n  authority: \"Europe PMC\"\n  title: \"Evidence cluster — Aquarium fish (teleost fish) toxicology (peer-reviewed, Europe PMC)\"\n  url: \"https://www.ebi.ac.uk/europepmc/\"\n  retrieved: \"2026-08-01\"\n  doc_type: \"first-hand abstracts (Europe PMC REST)\"\n  needs_review: false\ncopyright_note: \"Mixed licensing per COPYRIGHT_POLICY §3: Open Access (CC BY) studies retained verbatim with attribution; non-Open-Access studies paraphrased as derived fact summaries (numbers and proper nouns preserved, sentences rewritten).\"\nlicense: mixed\nauthority_tier: T2\nauthority_tier_basis: \"T2:oa-repo\"\nauthority_tier_date: 2026-08-04\n---\n\n# Evidence: Aquarium fish (teleost fish) toxicology\n\nSource: Europe PMC (Europe PubMed Central) REST search — first-hand peer-reviewed abstract records, pulled 2026-08-01.\nQueries covered toxicology, poisoning, intoxication, heavy metals, mycotoxins and (for relevant taxa) envenomation for teleost fish.\nThe cluster returns **11** representative studies with abstracts below. Abstract text is verbatim from source; each study is traceable by PMID.\n\n## Studies\n- **PMID 41870694 (2026, Environmental monitoring and assessment)** — Time and contamination level dependence of metal bioaccumulation and multibiomarker responses in fish: implications for biomonitoring.. Abstract (opening): This study evaluated how different levels of sediment metal contamination (ranging from below to above toxicity thresholds) and exposure durations (3-14 days) influence metal bioaccumulation and biomarker responses in fish under estuarine conditions. Using an integrated biomarker approach, the relationships among environmental contamination, metal accumulation, and fish health were examined to improve biomonitoring strategies. At the highest contamination level, 100% mortality was observed. Under low contamination, fish eliminated excess Cu, Zn, and Hg, whereas moderate contamination resulted in progressive accumulation of Cu and Zn; Pb accumulated under both exposure levels. Early biomarker responses included decreased GSH, inhibited GPx, increased lipid peroxidation, histopathological liver lesions, and neurotoxicity, followed by partial recovery. DNA damage increased over time and across contamination levels, likely due to impaired antioxidant defenses and/or direct metal-DNA interactions. Histopathological alterations were more strongly associated with sediment contamination than with tissue concentrations, indicating that body burdens may not fully represent exposure. GSH depletion and DNA damage were the most consistent biomarkers, whereas LPO and histopathology were sensitive primarily at early exposure stages. These findings reinforce the importance of considering both exposure duration and contamination level when interpreting biomarker responses and highlight the limitations of short-term or single-biomarker assessments. Biological effects detected at low to moderate contamination support the need for more precautionary sediment-quality thresholds. Overall, integrating biochemical, physiological, and histological biomarkers provides early detection of sublethal effects and a comprehensive assessment of ecosystem health. Consequently, a multibiomarker framework represents a powerful tool to strengthen the monitoring, evaluation, and management of aquatic environmental quality. *[CC BY — Open Access, verbatim with attribution.]*\n  Source: https://pubmed.ncbi.nlm.nih.gov/41870694/\n- **PMID 41060374 (2026, Conservation biology : the journal of the Society for Conservation Biology)** — Extent of threats to marine fish from the online aquarium trade in the United States.. Abstract (opening): The global marine aquarium hobby is a multibillion-dollar industry, largely driven by demand from the United States. Much of this trade occurs online. We web scraped 4 major US-based e-commerce platforms selling marine aquarium fish to determine the retail price and source (wild capture, aquaculture, or both) of 13 families of ray-finned marine fish (Actinopterygii). We supplemented this with ecological and economic trait data from FishBase and the International Union for Conservation of Nature (IUCN). Across all platforms and 13 popular fish taxonomic families, we found 734 unique species for sale, 89.2% (655 species) of which were sourced exclusively from the wild. A total of 45 species were of conservation concern (20 threatened species and 25 additional species with decreasing population trends), 38 of which were sourced solely from the wild. Retail price was significantly correlated with source, body length, minimum occupied depth, and schooling behavior. A further 100 species for sale were not listed as being in the aquarium trade in FishBase or by the IUCN, indicating incomplete information on this fishery in 2 important databases. For 58 species (encompassing 71 variants) with both wild-caught and captive-bred individuals for sale, aquaculture fish were a mean 28.1% (95% confidence interval 15.3) cheaper than their wild-caught counterparts. *[CC BY — Open Access, verbatim with attribution.]*\n  Source: https://pubmed.ncbi.nlm.nih.gov/41060374/\n- **PMID 41857250 (2026, Parasitology research)** — First record of Camallanus cotti (Fujita, 1927) in traded guppies (Poecilia reticulata) from India.. Abstract (opening): The guppy Poecilia reticulata is a widely traded ornamental fish species, valued for its popularity in aquariums globally. Parasitic infections pose a significant threat to both ornamental culture and native fish populations. This study records the first occurrence of the intestinal nematode Camallanus cotti (Fujita, 1927) in guppies from India, confirmed through both morphological and molecular analysis. Sixteen guppies were collected from the Kolathur ornamental fish market, Chennai, Tamil Nadu. Examination revealed that 11 fish (68.75%) were infected with red thread-like nematodes protruding from the anus. A total of 41 worms were recovered, with a mean intensity of 3.73 and a mean abundance of 2.56 worms per fish. Light microscopy confirmed diagnostic features of C. cotti, including the robust cephalic capsule and scanning electron microscopy illustrates the attachment of the parasite to intestinal wall. Molecular characterization using 18 S rRNA gene sequencing (GenBank Accession PX446961.1) showed 99.84% similarity with reference sequences, validating the morphological identification. Infected guppies exhibited visible clinical signs, including abdominal distension and threadlike worms protruding from the anus. The findings highlight the risk posed by C. cotti to ornamental fish health and emphasize the importance of quarantine, monitoring, and surveillance to prevent its spread through the aquarium trade. *[CC BY — Open Access, verbatim with attribution.]*\n  Source: https://pubmed.ncbi.nlm.nih.gov/41857250/\n- **PMID 40810320 (2026, Journal of fish diseases)** — Effects of Increased Water Salinity and Temperature on the Development of Rainbow Trout Fry Syndrome (RTFS) Caused by Flavobacterium psychrophilum.. Abstract (opening): Flavobacterium psychrophilum, the etiological agent of Rainbow Trout Fry Syndrome (RTFS) and Bacterial Coldwater Disease (BCWD), causes varying degrees of disease and mortality in salmonid aquaculture worldwide. Because its treatment relies on the use of antimicrobials, alternative interventions are of environmental and economic interest. As for other bacterial diseases, environmental factors like water parameters play a crucial role in the development of RTFS. In this study, we investigated the effect of either increased water salinity [1% (10 g L<sup>-1</sup>)] or water temperature (18°C ± 1°C) on the development of RTFS following challenge with F. psychrophilum in rainbow trout fry under experimental conditions (either bath challenge or co-habitation challenge). When implemented after bath challenge, the salinity treatment delayed the appearance of clinical disease, while the temperature treatment reduced the incubation time to appearance of clinical disease. Given the positive effect of increased salinity, we further assessed the effect of the salinity treatment on disease transmission when the fish were exposed to co-habitation challenge. While intraperitoneally injected seeder fish died within 2 weeks independent of salinity, cohabitant fish kept in water with 1% salinity had a significant increase in survival (42.6%) compared to the positive controls (17.9%). Infected dead and moribund fish were confirmed positive for F. psychrophilum. Increasing water salinity thus delayed and partly prevented RTFS. In applied terms, such a delay may give time to achieve antimicrobial susceptibility test (AST) results and initiate treatment before reaching heavy mortalities in a fish batch. Further studies should evaluate the robustness of the preventive effect of this approach, its effect on the microbial communities (fish and farm environment) and whether it could be combined with other measures (e.g., phage therapy). The effect of the warm water was surprising, as F. psychrophilum infections are reported at colder temperatures. *[CC BY — Open Access, verbatim with attribution.]*\n  Source: https://pubmed.ncbi.nlm.nih.gov/40810320/\n- **PMID 42456866 (2026, Fish & shellfish immunology)** — *[Paraphrased derived summary — non-Open-Access source.]* A novel grass carp (Ctenopharyngodon idella) brain-derived cell line (CIB), subcultured over 100 times with a diploid count of 2n=48 and 62.4% transfection efficiency, was shown susceptible to grass carp reovirus genotype I and responsive to poly(I:C) via interferon signalling. Electroporation of a CRISPR/Cas9 ribonucleoprotein achieved the first large-fragment gene knockout in cultured grass carp cells and a homozygous clonal line with enhanced antiviral response, providing a tool for gene-function and host-virus studies in teleosts.\n  Source: https://pubmed.ncbi.nlm.nih.gov/42456866/\n- **PMID 41703611 (2026, Environmental toxicology and chemistry)** — *[Paraphrased derived summary — non-Open-Access source.]* Zebrafish (Danio rerio) early-life stages exposed to water-accommodated fractions from the Brazilian oil spill showed developmental delay and increased malformations (thrombosis, deformed heart, pericardial/yolk-sac oedema, spinal kyphosis) at 16.47 and 32.95 microg-summed-PAH/L, effects worsening with temperature (28, 30, 32 C) - including incomplete mandible development absent at 28 C. Total length, eye, and swim-bladder area declined with both PAH concentration and temperature (additive interaction), and acetylcholinesterase activity rose with temperature but fell with PAH exposure, indicating temperature must be factored into oil-spill risk assessment under climate change.\n  Source: https://pubmed.ncbi.nlm.nih.gov/41703611/\n- **PMID 41640276 (2026, FEBS letters)** — *[Paraphrased derived summary — non-Open-Access source.]* This perspective argues that teleost immunotoxicology should move beyond cataloguing stressors toward a mechanistic, integrative framework using omics, in vivo tracking, and cross-disciplinary modelling, with immune function serving both as a mechanistic lens and a health indicator. It highlights persistent gaps in immune mechanisms, toxicokinetics, and multi-stressor interactions, and contends that such a framework would improve predictive risk assessment and our understanding of contaminant effects on disease susceptibility and population viability.\n  Source: https://pubmed.ncbi.nlm.nih.gov/41640276/\n- **PMID 40902923 (2026, Comparative biochemistry and physiology. Toxicology & pharmacology : CBP)** — *[Paraphrased derived summary — non-Open-Access source.]* Goldfish (Carassius auratus) exposed for one week to an environmentally relevant mixture of eight pesticides (low and high doses) showed kidney histopathology - glomerular shrinkage, enlarged Bowman's space, and degraded glomerular cells - plus melano-macrophage centres; expression of renin, nitrotyrosine and dinitrophenyl proteins, SOD, and apoptotic nuclei rose while catalase fell, indicating cellular damage and disrupted osmoregulatory and antioxidant defences (abstract truncated; full biomarker detail not retrievable from the non-Open-Access record).\n  Source: https://pubmed.ncbi.nlm.nih.gov/40902923/\n- **PMID 41727407 (2026, Toxicology reports)** — Direct adverse effects of fipronil sulfone, diisopentyl phthalate and disperse red 60 on zebrafish hepatocytes.. Abstract (opening): The major concerns about emerging pollutants fipronil sulfone, disperse red 60 (DR60), and diisopentyl phthalate (DiPP) include their environmental persistence, difficulty in its removal from water sources, and bioaccumulation in aquatic organisms. They could eventually enter the food chain and raise potential risks to human health. This research investigated whether the above-mentioned emerging contaminants directly affect cellular processes supporting metabolic homeostasis and female reproductive success in teleost fish, using zebrafish hepatocytes (ZFL liver cell line) <i>in vitro</i>. RT-qPCR analysis demonstrated that exposure to all three chemicals led to significant alterations in several key reproductive and metabolic genes. For example, DiPP and DR60 caused an increase in cytochrome P450 family 1 alpha (<i>cyp1α</i>), kisspeptin 1 (<i>kiss1</i>), and vitellogenin 1 (<i>vtg1</i>), and a decrease in cytochrome P450 family 3 subfamily A polypeptide 65 (<i>cyp3a65</i>) and peroxisome proliferator activated receptor alpha (<i>pparα</i>). A significant increase in cellular vitellogenin and triglyceride levels was also caused by all three compounds. Additionally, triglyceride levels in ZFL cells were increased by all three compounds, consistent with a gene expression profile, suggestive of a metabolic shift favoring lipid storage over catabolism. These findings show direct cellular adverse effects for fipronil sulfone, DiPP, and DR60, even at low yet environmentally relevant concentrations. The outcomes suggest their potential to disrupt metabolic and reproductive processes in teleosts <i>in vivo</i>. *[CC BY — Open Access, verbatim with attribution.]*\n  Source: https://pubmed.ncbi.nlm.nih.gov/41727407/\n- **PMID 41823821 (2026, Biology)** — Behavioral Alterations in Male Zebrafish After Administration of Androgen Receptor Blockers and an Activator.. Abstract (opening): Androgen receptor (AR) signaling is crucial for mediating male-typical behaviors across vertebrates. Enzalutamide (ENZ) and apalutamide (APA) are two second-generation androgen receptor inhibitors (SGARIs) that have been primarily used in the treatment of prostate cancer. However, these drugs still possess side effects, and there remains limited information regarding their behavioral and neurophysiological impacts following chronic exposure in non-mammalian animal models, particularly in fish. Thus, this study aimed to evaluate the behavioral alterations in adult male zebrafish (<i>Danio rerio</i>) following exposure to specific AR blockers (ENZ and APA) and an activator, dihydrotestosterone (DHT), to provide a comprehensive comparison between each tested drug. Adult male zebrafish were exposed via aqueous immersion to each compound at a 1 ppm concentration for ~2 weeks and were subjected to a battery of behavioral tests. From the results, both AR blockers were found to slightly compromise fish locomotion, with contrary results observed in DHT-treated fish, which displayed an increased locomotor activity together with slight alterations in fish exploratory behaviors. Furthermore, ENZ also caused a tightened shoal formation in zebrafish, while exposure to APA was observed to slightly diminish the fear response of fish. On the other hand, the DHT-treated group displayed a higher level of aggression compared to the vehicle control group. In conclusion, functional modulation of androgen receptor signaling leads to significant alterations in male zebrafish behavior, particularly affecting fear responses, aggression, and anxiety-related behaviors. We believe that these findings could contribute to a deeper understanding of the relationship between androgens and behaviors in vertebrates, especially zebrafish. *[CC BY — Open Access, verbatim with attribution.]*\n  Source: https://pubmed.ncbi.nlm.nih.gov/41823821/\n- **PMID 40898728 (2026, Journal of applied toxicology : JAT)** — A Multimodal Approach to Identify Metallothionein Metal Inducers in Nile Tilapia: Insights From Molecular Docking and Hepatocyte Exposure.. Abstract (opening): Many human activities contribute to the pollution of aquatic ecosystems, primarily through agricultural, industrial, mining, and domestic discharges into water bodies. Fish, being highly sensitive to environmental changes, serve as valuable models for monitoring the health of these ecosystems. Metallothionein (Mt), a biomarker for metal contamination, shows variable expression depending on the metal involved. Transcription of the mt gene is regulated by intracellular metal concentrations and mediated by interactions between metal-responsive transcription factors (Mtf) and metal response elements (MRE) in the mt promoter. Zinc plays a key role by binding to Mtf, activating it, and enabling interaction with MRE sequences to initiate transcription. In this context, this study aimed to identify the most potent inducers of mt expression in Oreochromis niloticus. Initially, zinc-binding proteins from O. niloticus were modeled to assess differential binding scores of various metals using molecular docking, which suggested the potency ranking Cd<sup>2+</sup> > Cu<sup>2+</sup> > Mn<sup>2+</sup> > Hg<sup>2+</sup> > Pb<sup>2+</sup>. These predictions were validated using primary hepatocytes exposed to concentrations 10 times higher than the maximum allowed for effluent discharge under Brazilian law. The expression of both mt mRNA and Mt protein was evaluated in hepatocytes. Both in silico and in vitro results identified cadmium as the most potent inducer of Mt. Other metals did not induce mt expression under the tested conditions. These findings underscore the importance of understanding how Mt expression varies by metal and tissue, as differences in responsiveness can influence the interpretation of Mt levels in teleost fish used for water quality monitoring and environmental toxicology. *[CC BY — Open Access, verbatim with attribution.]*\n  Source: https://pubmed.ncbi.nlm.nih.gov/40898728/\n\nSource text: `pdf-raw/evidence/europepmc_fish_toxicology_2026-08-01.txt` (Europe PMC first-hand abstracts, pulled 2026-08-01).\n\n## License & attribution\n\nMixed licensing per COPYRIGHT_POLICY §3: Open Access (CC BY / CC BY-NC /\nCC BY-NC-ND) studies are reproduced verbatim with attribution under their specific\nCC license; non-Open-Access studies are paraphrased as derived fact summaries\n(numbers and proper nouns preserved, sentences rewritten). Original records:\n- https://pubmed.ncbi.nlm.nih.gov/41870694/\n- https://pubmed.ncbi.nlm.nih.gov/41060374/\n- https://pubmed.ncbi.nlm.nih.gov/41857250/\n- https://pubmed.ncbi.nlm.nih.gov/40810320/\n- https://pubmed.ncbi.nlm.nih.gov/42456866/\n- https://pubmed.ncbi.nlm.nih.gov/41703611/\n- https://pubmed.ncbi.nlm.nih.gov/41640276/\n- https://pubmed.ncbi.nlm.nih.gov/40902923/\n- https://pubmed.ncbi.nlm.nih.gov/41727407/\n- https://pubmed.ncbi.nlm.nih.gov/41823821/\n- https://pubmed.ncbi.nlm.nih.gov/40898728/\n\n## Cleaning removal log (2026-08-05, codebuddy)\nPMID 41719136 — Xenopus tadpole blastomere-injection protocol (frog/amphibian), not fish\n","sources":["Europe PMC — Evidence cluster — Aquarium fish (teleost fish) toxicology (peer-reviewed, Europe PMC) (retrieved 2026-08-01)"],"source":{"authority":"Europe PMC","title":"Evidence cluster — Aquarium fish (teleost fish) toxicology (peer-reviewed, Europe PMC)","url":"https://pubmed.ncbi.nlm.nih.gov/41870694/","retrieved":"2026-08-01","ref":"PMID 41870694","doc_type":"official PDF","source_document":"Peer-reviewed Aquarium fish toxicology literature (Europe PMC, first-hand abstracts)","verification_file":"pdf-raw/evidence/europepmc_fish_toxicology_2026-08-01.txt"},"source_document":"Peer-reviewed Aquarium fish toxicology literature (Europe PMC, first-hand abstracts)","source_file":"pdf-raw/evidence/europepmc_fish_toxicology_2026-08-01.txt","trust":{"authority_tier":"T2","fidelity":"paraphrase","license":"mixed","display_grade":"B"},"tokens_estimated":600,"generated_at":null,"tip":"Use /api/v1/topics to discover more topics. /api/v1/nutrient for precise single-point queries. /api/v1/cross_compare for 2-3 standard comparisons."}