New substances: risk assessment, new substances notification 22084

Name of company: GloFish LLC

First day of assessment period: January 23, 2025

Last day of assessment period: May 22, 2025

Identity: A genetically modified Corydoras aeneus descended from Green Corydora 0, founder of the GCA2021-0 line, with multiple copies inserted of a construct containing genes expressing a green fluorescent protein derived from a foreign organism

• Corydoras aeneus GCA2021-0
• Common names: corydoras, corys, bronze corydoras
• Trade name: GloFish® Electric Green® Corydoras

Organism type: Fish

Activity: Import of ornamental fish from the United States for home aquaria

Assessment level of concern:

• Human health hazard: Low
• Human exposure: Low to medium
• Environmental hazard: Low
• Environmental exposure: Low

Assessment conclusion under section 64 of the Canadian Environmental Protection Act, 1999: Not suspected to be toxic.

Recommended action: None

Waiver: None

Synopsis

Corydoras aeneus GCA2021, also known as the GloFish® Electric Green® Cory, was notified for import and subsequent use as an ornamental fish in home aquaria. Given the organism’s eligibility for listing on the Domestic Substances List (DSL), other potential uses were considered in the assessment. Potential uses of GCA2021 could include release or culturing in outdoor ponds, as an environmental sentinel, as bait fish, as well as in scientific research and for future manufacture in Canada. There is no evidence to suggest a potential risk of adverse environmental effects at the exposure levels predicted for the environment, from the notified use as an ornamental fish in home aquaria. The potential risk of adverse environmental effects remains low despite the identified potential uses. Owing to the low potential for hazard and the low potential for exposure, the risk to the environment associated with C. aeneus GCA2021 is not suspected to meet the criteria in paragraphs 64(a) or (b) of the Canadian Environmental Protection Act, 1999 (CEPA). Similarly, there is no evidence to suggest a risk of adverse human health effects at the exposure levels predicted for people living in Canada from use as an ornamental aquarium fish as well as other identified potential uses. Owing to the low potential for hazard and the low to medium potential for exposure, C. aeneus GCA2021 is not suspected to meet the criteria in paragraph 64(c) of CEPA.

Corydoras aeneus GCA2021: background information

The notified organism Corydoras aeneus GCA2021 is a genetically modified fluorescent bronze corydoras. It contains a transgene expressing a fluorescent protein which makes the fish appear green under ambient light, including sunlight. GCA2021 was derived from a domesticated strain of albino bronze corydoras. C. aeneus is a small tropical freshwater fish that has been available worldwide as a home aquarium fish since the 1930s (Innes, 1935). The amino acid sequence used for the development of GCA2021 is correspondingly 100% identical to those used for the GloFish® Electric Green® Tetra, Betta, Barb, Pristella, and Shark.

GCA2021 will be imported from the United States, for use as an ornamental fish in home aquaria and will be marketed throughout Canada under the trade name GloFish® Electric Green® Cory. GCA2021 received its Enforcement Discretion decision by the U.S. Food and Drug Administration in 2022 and has been commercially available in the United States since September 2022.

Context of this risk assessment: joint effort between departments

On January 22, 2025, a notification under the New Substances Notification Regulations (Organisms) (NSNR(O)) was submitted by GloFish LLC to Environment and Climate Change Canada (ECCC) for the GloFish® Electric Green® Cory (GCA2021), a genetically modified bronze corydoras (C. aeneus), for use as an ornamental fish in home aquaria. Under a Memorandum of Understanding (MOU) between the Department of Fisheries and Oceans (DFO), Environment and Climate Change Canada (ECCC) and Health Canada (HC), DFO conducted an environmental risk assessment, and collaborated with HC to conduct an indirect human health risk assessment of the submitted information. As part of this collaboration, the services of the Canadian Science Advisory Secretariat (CSAS) were used to apply a peer review process to strengthen the scientific basis of these assessments, the result of which was a Science Advisory Report (SAR) (DFO, 2025). The SAR provided the peer-reviewed science advice to ECCC and HC, which was used to inform the risk assessment decision under CEPA. The SAR is publicly available on the CSAS website.

Hazard assessment

The environmental hazard potential of C. aeneus GCA2021 is assessed to be low because:

1. GCA2021 is not likely to produce toxins that could affect other plant and animal species if released in the environment. The amino acid sequence of the green fluorescent protein is the same as that used in the previously assessed GloFish® Electric Green® Shark, Pristella, Barb, and Tetra. These lines have been in commercial production in the U.S. for several years with no reports of toxic effects
2. The introduction of the fluorescence transgene through horizontal gene transfer to a novel host is not likely to result in harmful effects as genes that encode fluorescent proteins have been introduced to a wide range of organisms with few reports of harmful effects
3. There is no direct evidence that the expressed fluorescent protein produced by GCA2021 would increase the hazard to the environment relative to non-transgenic C. aeneus
4. Based on the information available, the potential for GCA2021 to have an altered capacity as a vector for disease relative to non-transgenic C. aeneus is negligible
5. Test data indicates that GCA2021 has a slightly higher temperature at which 50% of the fish died than that of the non-transgenic C. aeneus, demonstrating similar sensitivity to cold water temperatures
6. GCA2021 are modified versions of wild bronze C. aeneus, which are freshwater fish of the family Callichthyidae. These C. aeneus are naturally distributed throughout South America on the eastern side of the Andes, from Columbia and Trinidad south to the Rio de la Plata basin in Brazil and Argentina, and their optimal survival temperatures in the environment are within the range of 25°C to 28°C. Canada does not have native species of C. aeneus or any other Callichthyidae family fish. In addition, the lower water temperature in Canadian lakes (not consistently above 7°C) as compared to tropical ones, make induced breeding of accidentally released C. aeneus highly unlikely. Therefore, there is low potential for GCA2021 to cause hazard through natural hybridization with native fish in Canada
7. In the wild, C. aeneus are not known to build structures that are expected to impact habitats of other species and there are no reports of GCA2021 having altered behaviour, relative to their domesticated non-transgenic counterparts; and
8. GCA2021 would be expected to contribute to nutrient cycles within habitats if released, through the ingestion of prey and other food items and the release of waste (ammonia and feces). While the potential effects of the fluorescent protein in GCA2021 on metabolism, and hence nutrient cycling, have not been studied, its impact is expected to be negligible. This is based on the likelihood of low numbers of individuals that could be released into an ecosystem and the small size of the corydoras

The human hazard potential of C. aeneus GCA2021 is assessed to be low because:

1. GCA2021 is a genetically modified tropical fish containing copies of a transgene at a single site of insertion in its genome. Although alternate insertion patterns may exist in the population, phenotypic stability was demonstrated for the notified organism when prescribed breeding and maintenance protocols (for example, controlled breeding, selection) were used
2. The genetic modifications used to produce GCA2021, including CRISPR/Cas9, do not raise human health concerns. While unintended effects cannot be fully excluded, off-target effects from the transgene would be removed from the population and not used in any line propagation. The inserted genetic material shows no similarity to known human toxins or pathogens; thus, there is no evidence of risk to humans
3. While there are reported cases of zoonotic infections (infections caused by germs that spread from animals to humans) associated with tropical aquarium fish, particularly for immunocompromised individuals and children, there are no reported cases attributed to any of the commercially available lines of GloFish® or to wild-type C. aeneus. The zoonotic potential of GCA2021 is not expected to be any different than for wild-type C. aeneus currently commercially available
4. Sequence analysis of the inserted transgene did not match any allergens known to be relevant for human health. The amino acid sequence of the fluorescent protein is identical to that used in GloFish® Electric Green® Tetra, Betta, Barb, Pristella, and Shark lines previously notified and assessed by the program; and
5. There is a history of safe use for GCA2021 in the United States, albeit limited, since the organism has only been commercially available since September 2022. However, the wild-type species has been used globally as an ornamental aquarium fish since the 1930s. Likewise, no adverse human health effects have been reported for the other commercially available lines of GloFish®

Hazards related to organisms used in the workplace should be classified accordingly under the Workplace Hazardous Materials Information System (WHMIS)^{Footnote 1}.

Exposure assessment

The environmental exposure potential of C. aeneus GCA2021 is assessed to be low because:

1. The intended use of GCA2021 is limited to indoor aquaria
2. There are no lakes in Canada that consistently remain above 7°C throughout the entire course of a year, or above 6°C across multiple years. Therefore, should GCA2021 be released accidentally or intentionally into the environment the low winter temperatures in Canadian lakes and rivers will limit the ability and the capacity for the fish to establish themselves in the Canadian environment
3. Isolated opportunities for reproduction may occur in a few Canadian lakes that have temperatures in the mid 20°C range for a short period during the summer months as the reported optimal survival temperatures for C. aeneus range from 22°C to 29°C in the aquarium and they have an optimal temperature of 20°C for hatching. This short window could lead to a seasonal occurrence, potentially with localized overwintering pockets in specific environments like industrial effluent, hot springs, or isolated lakes. While this may provide a tolerable temperature range for reproduction, other environmental conditions required for spawning would need to be met such as the seasonal changes in water temperature and chemistry. These conditions are unlikely, due to the seasonal differences between Canada and South America
4. Given that global climate change is making Canadian lakes warmer, it is possible that fish with moderate cold tolerance could survive in more lakes by 2063 (DFO, 2013). However, the data shows that even with warmer water, this species is still not likely to survive in Canadian waters; and
5. Reproduction of C. aeneus GCA2021 in home aquaria is highly unlikely, given the specific conditions required

The human exposure potential of C. aeneus GCA2021 is assessed to be low to medium because:

1. The adult fish of GCA2021 will be imported into Canada and distributed to about 500 retail outlets for use as an ornamental aquarium fish, thus limiting potential exposure primarily to those who purchase it for a home aquarium. Typical human exposure to live or dead fish is expected to be related to maintenance activities, such as tank cleanings and water changes;
2. Like other aquarium fish, humans exposed to these fish may include groups of individuals who may be more vulnerable due to greater susceptibility (for example, persons who are immunosuppressed, or with underlying health conditions);
3. Human exposure to GCA2021 from environmental exposures is expected to be limited;
4. Disposal of live or dead GCA2021 is not expected to result in survival and establishment of GCA2021 in the natural environment. The fluorescent protein would also be expected to degrade over time; and
5. Potential uses of GCA2021 if this organism were added to the Domestic Substances List, could include for use in outdoor ponds, pollution detection, for bait, or for scientific research. It could also potentially be produced in Canada. None of these potential uses would result in higher human exposures than what has been characterized for the notified use.

Risk characterization

Owing to the low potential hazard and the low potential exposure, the environmental risk associated with the use of C. aeneus GCA2021 as an ornamental aquarium fish is assessed to be low. Owing to the low potential hazard and the low potential exposure from other potential uses the environmental risk associated with the use of GCA2021 for those uses is not expected to increase significantly and would not be of concern.

Owing to the low potential hazard and the low to medium potential exposure, the human health risk associated with the use of C. aeneus GCA2021 as an ornamental aquarium fish or the potential uses is assessed to be low.

Risk assessment conclusion

There is no evidence to suggest a potential risk of adverse environmental effects at the exposure levels predicted for the environment from the use of C. aeneus GCA2021 as an ornamental aquarium fish, nor from any uses that may result in introduction of the fish into the Canadian environment. The risk to the environment associated with C. aeneus GCA2021 is not suspected to meet the criteria in paragraphs 64(a) or (b) of CEPA. No further action is recommended.

Similarly, there is no evidence to suggest a potential risk of adverse human health effects at the exposure levels predicted for the people living in Canada from the intended and potential uses of GCA2021. The risk to human health associated with C. aeneus GCA2021 is not suspected to meet the criteria in paragraph 64(c) of CEPA. No further action is recommended.

References

DFO. 2013. Risk-based assessment of climate change impacts and risks on the biological systems and infrastructure within Fisheries and Oceans Canada's mandate - Freshwater Large Aquatic Basin. DFO Can. Sci. Advis. Sec. Sci. Resp. 2013/011.

DFO. 2025. Environmental and indirect human health risk assessment of the GloFish® Electric Green®, Sunburst Orange®, and Moonrise Pink® corydoras (Corydoras aeneus): three lines of transgenic ornamental fishes. DFO Can. Sci. Advis. Sec. Sci. Advis. Rep. 2025/053.

Innes, W.T. 1935. Exotic aquarium fishes: a work of general reference. (second edition) Philadelphia: Innes Publishing Company.