Understanding the impacts of non-native species on the environment, economics, and society is critical for management and policy decision-making. Generalizing impacts across taxa and regions is a daunting task due to the complexity and range of effects, the interaction of invasive species impacts with other environmental stressors, and the differing human perceptions of effects and of costs and benefits. Despite these complexities, general frameworks for quantification of ecological impacts of non-natives have been proposed. We modified the Generic Impact Scoring System (GISS) to more adequately assess nonnative fish impacts to Peninsular Florida and applied it to assess the impacts of 32 nonnative freshwater fishes that have successfully established in the region. We also used life history traits of the species to predict level of impact and identify traits that may be associated with more severe impacts to peninsular Florida. Results suggest that overall, nonnative fishes in peninsular Florida have relatively low impacts compared with other regions. Less than 20% of fishes assessed had moderate impact GISS scores and none of the assessed species had scores indicating high impact. We found that species with higher impact scores tended to have lower swim factors, higher parental care, and a more benthic position in the water column. These analyses will be useful for managers as they work to understand the impacts of species established in Florida, and potential impacts of species yet to establish.

Biotic resistance theory posits a negative relationship between diversity and invasibility. The mechanisms behind this can be variable, but studies are often focused on competition between many resident and introduced species. However, individual species may interact more strongly in communities, some of which may be effective predators and, thus, could offer stronger biotic resistance, broadening biotic resistance theory beyond diversity. In species with complex life histories, biotic resistance may be stage-specific, with resisting species affecting select life stages. The relationship between native eastern mosquitofish (Gambusia holbrooki) and the non-native tropical clawed frog (Xenopus tropicalis; TCF), provides a model system to investigate stage-specific biotic resistance. Preliminary observations suggest TCFs in their introduced range in Florida, USA are more likely to occupy ponds without fish and we hypothesise that mosquitofish provide predatory biotic resistance to early TCF life stages. We tested the hypothesis that the strength of predatory biotic resistance to species with complex life histories would be based on life stage. We also examined how the strength of predatory biotic resistance can be mitigated by predator density, cannibalism by adult life stages and habitat complexity. Hypotheses were tested using wild-caught and lab-reared individuals in controlled laboratory experiments. Early TCF life stages, lacking defensive traits, suffer near-total mortality due to predation and harassment, with vulnerability decreasing during and after metamorphosis. Mosquitofish density and habitat complexity had minimal effects, while the combination of adult frogs and mosquitofish resulted in facilitation between the two predators, increasing tadpole predation. This study underscores the need for thorough testing of the biotic resistance hypothesis across life stages and shows promise for the control of TCFs in Florida. Mosquitofish could be used as a biological control to reduce the recruitment of TCFs by eliminating the larval stage.

Phase shifts can occur in ecosystems because of external stressors. Such transitions from one state (e.g., clear water, seagrass) to another (e.g., phytoplankton blooms, bare substrate) continue to be documented worldwide. In estuaries, stressors related to urban and suburban development are often implicated in phase shifts, including altered hydrology and eutrophication. Tidal creeks may be especially prone to phase shifts as their position in the landscape exposes them to the brunt of coastal development. In 2017, a precipitous seagrass decline occurred in a tidal creek downstream of coastal development in the Charlotte Harbor estuary, Florida (USA). Fisheries independent monitoring data (July 2014 to June 2022) from 21.3 m seines were used to investigate changes in fish assemblages. Multivariate analyses identified a fish assemblage shift that coincided with seagrass loss and increasing algal blooms. Reductions in seagrass-associated species (e.g., Rainwater Killifish Lucania parva) were offset by increases in generalist and planktivorous taxa (e.g., Bay Anchovy Anchoa mitchilli). Such changes did not occur in neighboring creeks downstream of more natural habitat. The present study is indicative of a potential phase shift. Tidal creeks serve as ‘sentinels’ for ecosystem change. Furthermore, similar patterns of seagrass loss and algal blooms are taking place in the open estuary; thus, the fish assemblage shift identified in the tidal creek may signal similar, widespread changes. Identifying shifts in biotic assemblages and predominant drivers can help guide resource planning to strengthen ecosystem resilience and recovery within Charlotte Harbor and other Florida estuaries.

Biological invasions, driven by the spread of non-native species, have become a critical global issue because of their far-reaching ecological and socioeconomic impacts. Effective communication of the risks of biological invasions is essential for implementing robust policy and legislation and gaining public support for conservation efforts. However, current policies often suffer from fragmentation and ineffectiveness, largely due to inadequate risk communication and complex multi-level governance. To address this challenge, we develop a global framework designed to enhance clearer communication about biological invasion risks. The framework contextualizes key terms across three domains in invasion science: species invasiveness, risk analysis, and decision support tools. Using both diffusion-of-English and ecology-of-language paradigms, and following a three-step process involving preliminary consensus, AI querying, and ground-truthing with final consensus, we validate the framework in 70 non-English languages which, together with English, have official status in at least one country and collectively cover all 195 countries worldwide. Our findings reveal that while terminology for risk analysis is well established, terminology for species invasiveness and, especially, for decision support tools remains underdeveloped in many languages, hindering effective communication and policy implementation. Our framework underscores the importance of cultural and political neutrality. By promoting clearer risk communication among scientists, policymakers, and the public globally, we aim to reduce policy fragmentation and foster enhanced collaboration in risk mitigation. We recommend expanding multilingual decision support tools to include the full risk analysis process: risk identification, risk assessment, and risk management. This will support intergovernmental mitigation efforts and promote a unified global response to biological invasions.

Thermal tolerance can reveal the risk of establishment and spread for non-native tropical species introduced to more subtropical regions. These data are particularly important for novel introductions such as the Rio Cauca Caecilian (Typhlonectes natans), a species of amphibian established in Miami, Florida, United States of America (USA). To estimate its thermal tolerance T. natans individuals were captured with baited traps, transported to the laboratory, and acclimated to 25°C. We used chronic lethal methodology to estimate three cold tolerance endpoints: cessation of feeding, loss of equilibrium, and death. This methodology utilizes a 1°C per day temperature change which allows for stepwise reacclimation. Endpoints were 18.61°C ± 0.91, 17.08–20.56 (mean ± SD, range) for cessation of feeding, 13.61°C ± 0.81, 12.68–14.98 for loss of equilibrium and 12.45°C ± 0.49, 11.72–13.84 for death. The chronic lethal minimum temperature is relatively high for an established aquatic species in Florida, suggesting water temperature may limit its northward spread. Thermal tolerance attributes are one aspect of the risk of spread, and some information gaps remain, including salinity and desiccation tolerance, attributes that could allow movement between coastal watersheds and persistence in seasonal wetlands.

Objective We investigated the influence of body size and salinity on the thermal tolerance of Common Snook Centropomus undecimalis (hereafter, "snook").Methods Juvenile snook (small = 59-156 mm standard length, large = 188-341 mm standard length) were collected from Tampa Bay, Florida. Snook were acclimated in a recirculating aquaculture system, where they underwent a quarantine period at 25 degrees C with gradual salinity adjustments to either 3, 15, or 30 parts per thousand for large juveniles and 3 parts per thousand for small juveniles. Snook were then randomly selected for chronic lethal minimum trials during which temperature was decreased by 1 degrees C per day. Temperatures at which the fish ceased feeding, lost equilibrium, and died were recorded.Results In the chronic lethal minimum trials, small juvenile snook exhibited greater cold tolerance for two end points-cessation of feeding and death-compared with larger juveniles at 3 parts per thousand. For large juveniles, death occurred at lower temperatures in both the low- and high-salinity trials (9.2 degrees C) than in the midsalinity trials (10.1 degrees C) (i.e., fish were less hardy at midsalinity). In the low-salinity trial for large juveniles, cessation of feeding (16.1 degrees C) occurred before the other salinity trials for large juveniles as water temperatures were lowered, but loss of equilibrium occurred after (10.1 degrees C).Conclusions Juvenile snook undergo complex ontogenetic changes resulting in reduced cold tolerance in larger individuals. Salinity differences further modify cold tolerance. At the onset of a cold event, juvenile snook occupying waters of low salinity (i.e., rivers) are less likely to lose equilibrium, while those occupying waters of midsalinity are more likely to die if they cannot find adequate refuge from cold water. These observations likely apply to adult snook; thus, information on cold tolerance at various salinities, combined with knowledge of fish behavior, provides insights into factors affecting overwintering and snook resilience to climate variability, particularly as the species continues to expand its range north. This study documents that both size and salinity significantly influence the cold tolerance of juvenile Common Snook. The location of juvenile snook within the estuary at the onset of a cold event, whether in rivers or the lower estuary, can result in different survival outcomes. These findings provide valuable insights into how juvenile snook responded to cold events, informing management strategies as the species continues to expand its range.

In the early 1900s, eastern mosquitofish (Gambusia holbrooki) and western mosquitofish (Gambusia affinis) were deliberately and globally introduced for the biological control of mosquito larvae. Subsequently, both species developed a reputation for causing impacts on native small-bodied fish, amphibian larvae, and other aquatic species. This led to both species being considered some of the world’s worst invasive species. Due to morphological similarities, organizations worldwide often consider these species jointly when discussing their introduction and impacts. Recent studies suggest these species differ in fundamental ways, which could affect invasion success. Our goal was to compare eastern and western mosquitofish behavior and invasion success. Replicate populations were collected from the U.S. states of Florida (eastern mosquitofish) and Louisiana (western mosquitofish) to assess variation in aggression, boldness, and sociability. Mesocosm trials were used to compare invasion success between species following introduction to an ecosystem occupied by another small-bodied poeciliid. Eastern mosquitofish caused more damage to similar-sized heterospecifics and western mosquitofish exhibited greater boldness. No differences were found in sociability between the two species. In mesocosms, impacts were observed for both mosquitofish species but were greatest for heterospecifics with eastern mosquitofish. This suggests that two invasive species, even with similar life history and morphology, can differ in traits related to invasion success and ecological impacts. It is important to correctly identify mosquitofish species when evaluating their invasion.

As climate change leads to rising temperatures, tropical fishes such as common snook Centropomus undecimalis (hereafter snook) are expanding poleward, necessitating an understanding of their ability to tolerate cold temperatures and rapid temperature drops. To investigate this ability, we conducted chronic lethal minimum (CLmin) and critical thermal minimum (CTmin) trials in the laboratory using fish collected from a latitudinal gradient along the Gulf of Mexico coast of Florida. Individual lower lethal temperatures ranged from 7.9 to 10.5 °C. On average, the northernmost snook population exhibited the most cold hardiness, ceasing feeding at 14.4 °C and dying at 8.6 °C. These thermal endpoints were lower than for populations collected farther south and are significant in the context of passing cold fronts. In the CTmin trial that reduced water temperatures more quickly, and is sub-lethal, snook lost equilibrium at temperatures almost 2 °C warmer than those in our chronic trial, underscoring the necessity of simulating realistic cold events to fully understand species’ cold tolerance. These findings help managers predict the effects of variation in timing and extent of severe cold events on snook across different estuaries, allowing for targeted management approaches should conditions warrant actions to facilitate population recovery. Metrics associated with a species’ cold hardiness can inform climate modeling, fisheries management, and freshwater inflow regulations affecting thermal refugia, aiding in the management and conservation of tropical fish populations in the face of global climate change.

Movement is a key driver of population dynamics. Movement ability and propensity often vary among populations and individuals. These differences may be particularly strong in aquatic species, where the ability to move within a site is not necessarily correlated to the ability to move between sites. In periods of range expansion, these differences can lead to non-equilibrium dynamics, whereby more mobile phenotypes arrange themselves spatially. This can be even more pronounced when dispersal success is nonrandom with respect to a heritable trait, thus acting as an agent of selection. This process-dubbed spatial sorting-can be particularly pronounced in non-native species, often hastening the speed of invasion spread. However, before spatial sorting occurring, there must first be individual differences in traits that confer greater movement success. Recently, a high-density breeding and expanding population of the non-native pipid frog, Xenopus tropicalis, in west-central Florida, offering a great opportunity to test whether movement success is predicted by individual differences in morphology or locomotor capacity. To test this, we compared the morphology, maximal exertion capacity, and jumping performance of movers and residents. We found that relative to residents, movers had longer hindlimbs, wider ilia, and traveled for greater time intervals before reaching exhaustion. These results suggest functional morphological and physiological traits are important in determining inter-site movement success.

The United States imports thousands of live vertebrate species annually as part of legal trade. Escapes and releases from captivity are major pathways of invasion, however, the risk posed by the thousands of imported vertebrate species has not been systematically assessed. We conducted a horizon scan that used a data-driven climate match to filter a list of nearly 15,000 taxa drawn from across the globe of imported fish, amphibians, reptiles, birds, and mammals for rapid assessment by taxonomic experts. Experts evaluated 840 species and identified 32 (22 reptiles and 10 fishes) as having the highest risk for establishment, spread, and negative impacts. Of those high-risk species, the majority have the capacity to disrupt ecosystem processes via their role as top predators or the unique ecological niches that they occupy, while several of the snake species pose a threat to human health. High-risk species were often scored with high confidence while in contrast, low scores were attributed to a combination of ecological redundancy, low propagule pressure, or low climate match while low confidence arose from a lack of information in the literature (i.e., data deficiency). Our study therefore highlights legally imported species likely to cause the greatest harm with the recognition that many other species could also become invasive in the United States. The ranked list of vertebrate threats can be used to prioritize watchlists and inform the development of targeted regulations for importation can be applied to regions to provide a rapid, preliminary screening for large pools of potential invaders.

The spread of non-native species plays a substantial role in the designation of a species as invasive, yet the determination and measurement of non-native-species spread is challenging, particularly for fishes, which are limited by aquatic connectivity. Spread has been quantified for fishes in a variety of ways and exact methods vary by region and taxonomic group. In this study, we quantified fish spread in peninsular Florida and used life history traits to understand what factors contribute to the rate at which fish species spread. Using a variety of statistical analyses, we found that fast spreaders in peninsular Florida tend to have a larger body size, narrow diet, shorter time to hatch, greater salinity tolerance, and higher fecundity. However, some variables like parental care, egg diameter, and reproductive guild were the same or very similar across all established species that were included in the analyses. Predicting whether an established species will spread quickly or slowly in Florida may be more challenging than predicting whether an introduced fish species will establish, yet there is support across regions for the use of life history traits in the risk assessment process.

Understanding the dynamics of species invasions in aquatic ecosystems is crucial for conservation and management efforts. We investigated the influence of species interactions and habitat complexity on biotic resistance to invasion by small-bodied freshwater fishes in peninsular Florida. Specifically, we focused on the interactions between two native species, Florida bass (Micropterus salmoides) and eastern mosquitofish (Gambusia holbrooki), and a common invader, the green swordtail (Xiphophorus hellerii). Our experiments included tanks with varying levels of structural complexity to mimic different habitat types. The presence of both native species significantly reduced swordtail survival, but the effect varied depending on habitat complexity. In habitats with strong predation refuge, mosquitofish facilitated bass predation on swordtails, whereas in habitats with weak predation refuge, bass suppressed mosquitofish aggression, leading to interference. Mosquitofish predominantly occupied vegetated areas and aggressively interacted with swordtails, significantly reducing invader survival. Our findings highlight the importance of considering species interactions and habitat complexity in predicting biotic resistance to invasions. We conclude that diverse interactions among native species can either enhance or impede invasion resistance, with implications for conservation and management strategies. Further research is needed to understand the broader impacts of multiple predators and competitors on invader dynamics in aquatic ecosystems.

Worldwide, coastal wetlands are threatened by disrupted hydrology, urbanization, and sea-level rise. In southwest Florida, coastal wetlands include tidal creeks and coastal ponds, which are the primary habitats used by juvenile Tarpon, Megalops atlanticus, an important sport fish. Coastal ponds can occur near uplands and are ephemerally connected to the open estuary, creating conditions of variable dissolved oxygen and salinity. Juveniles can tolerate wide-ranging abiotic conditions, but little is known about how they egress from their remote nursery habitats, which often requires them to cross > 1 km of mangrove forest to reach the open estuary. The objective of this study was to (1) compare Tarpon body condition among ponds close to the open estuary versus those ponds farther away on the Cape Haze peninsula of Charlotte Harbor, Florida, and (2) using acoustic telemetry determine what factors contribute to Tarpon emigration from the ponds to open estuarine waters. We tested the hypothesis that distinct groups of Tarpon occur in isolated ponds, leading to variation in fish length and body condition, and that opportunities for emigration from these ponds hinge on high water events. No pond stood out as having Tarpon of low body condition. Factors contributing to increased probabilities of Tarpon emigration were low barometric pressure, high-water level, and Tarpon body length. Tarpon emigrated from ponds near tidal creeks during summer king tides, while tropical cyclone conditions were needed to allow for movement from ponds farther in the landscape. The juvenile Tarpon were later detected at the mouths of large rivers 30 km up-estuary. The characterizations of water levels and event criteria needed for successful Tarpon nurseries should aid in habitat conservation and the creation of Tarpon nursery habitat in restoration designs.

For non-native species, climate can act as a primary filter limiting establishment. Numerous studies examining climate similarity between native and introduced regions have been completed for temperate areas, however we know little about how well climate matching performs for warmer regions. For non-native freshwater fish introduced to warm regions, one potential problem with climate matching is that fish from both temperate and tropical source regions could establish. Our goal was to examine whether climate matching can predict the establishment of non-native freshwater fish for a warm climate region. We used CLIMATCH, a widely applied climate matching program, to analyze climate similarity between source and target regions for 37 successfully established species and 36 species that have failed to establish. CLIMATCH was calculated in two ways for successfully established species, with Florida records included ( post hoc ) and without Florida records ( a priori ). The mean post hoc score for successful species was higher than that of failed species; however, the mean a priori score for successful species did not significantly differ from failed species. On average, post hoc scores were inflated 1.5 times over a priori scores. The post hoc result is tautological—the scores are high because the species is successful, and the species is successful because the scores are high. These results highlight two issues for climate matching: (1) as commonly done post hoc , degree of climate match and predictive power may be overestimated and (2) a priori applications may lack predictive power. We recommend consideration of these issues in the use and interpretation of CLIMATCH for prediction. Additional research into regional importance of climate variables (temperature and precipitation) is warranted, especially in warm climate regions.

Thermal tolerance data are important for identifying the potential range of non-native species following introduction and establishment. Such data are particularly important for understanding invasion risks of tropical species introduced to temperate climates and identifying whether they can survive outside tropical regions. A breeding population of the tropical clawed frog (Xenopus tropicalis) was recently discovered in west-central Florida, U.S.A. This fully aquatic species is native to the rainforest belt of west Africa and has not been documented outside its native range. Because of the lack of invasion history, data are sparse on the thermal limits for this species. We used chronic lethal and critical thermal methodologies to investigate thermal tolerance on adult stages and critical thermal methods on tadpoles. Because of our use of both chronic and critical methodologies, we also examined the literature to reveal common methods used to investigate thermal minimum and maximum temperature in amphibians, which were found to be dominated by the critical maximum. Chronic lethal temperatures for adult X. tropicalis were 9.73°C and 36.68°C. Critical temperatures were affected by acclimation temperature and life stage; adults were more tolerant of extreme temperatures. Based on these critical thermal data and the fact that breeding tends to occur when temperatures are suitable for survival, tadpole stages are unlikely to be affected by extreme temperatures. Instead, range expansion in Florida will likely be limited by the adult stages. Our findings indicate that the tropical clawed frog could occupy much of southern Peninsular Florida and other tropical and subtropical regions worldwide.

Regulatory changes to the Lacey Act and recent petitions to add aquaculture species in trade to the list of injurious wildlife could lead to prohibitions of interstate movement of live aquatic organisms with the potential for unintended, negative economic consequences. In this analysis, the economic impact of the potential federal prohibition of interstate transport of seven aquaculture species (blue catfish, tilapia, red swamp crawfish, grass carp, koi, guppy, and goldfish) currently in trade was assessed. Total economic impact was estimated to be $452 million (USD) annually, with a loss of 4819 jobs and a loss of $35 million in tax revenue. Effects could potentially occur on the largest sectors of U.S. aquaculture in as many as 80% of U.S. states and result in negative economic effects on as much as 21% of U.S. aquaculture farms.

Abstract The process of domestication affects fitness following return to the wild. For the invasion of non-native species, however, captive rearing is thought to increase propagule pressure, the quantity and rate that individuals are introduced. Invasion success for domesticated species may represent a balance between survival and propagule pressure. Survival is likely affected by selective breeding (advertent versus inadvertent selection) and predator populations, which contribute to biotic resistance, the ability of communities to resist invasion. Ornamental species are subjected to deliberate selection (advertent) for phenotypic traits such as coloration, as is the case with the green swordtail (Xiphophorus hellerii). Wild-type varieties are also produced without deliberate selection (inadvertent) and resemble their wild counterparts. In Florida, swordtails are produced in aquaculture and propagule pressure is high, yet few colorful individuals are encountered in the wild. Here we examined how invasion success is influenced by the interactive effects of biotic resistance, selective breeding, and propagule pressure. We used outdoor ponds to examine intraspecific variation in invasion success for five swordtail varieties across increasing biotic resistance. Propagule pressure over 14 weeks was varied proportional to trade volume for the five varieties. Biotic resistance increased with community complexity and affected swordtail survival and reproduction. In control ponds the number of fish for each variety followed propagule size. Despite lower propagule pressure, the wild-type variety increased relative to the advertently produced varieties, but only in ponds with greater biotic resistance. These results suggest propagule pressure is attenuated by increased biotic resistance and deliberate breeding.

About 11 million marine ornamental fish of ca 1800 non-native species are imported into the USA each year. Selecting species for risk assessment is daunting for such a diverse pathway. Herein, we discuss a focused method for species selection: choosing important taxa related to known invaders in high-volume pathways and narrowing prospective species lists to manageable groups of potential hazards. We provide an example using 11 damselfishes, a family with high volume in trade and one of the species established in USA waters. We used a specialized literature review and a risk screening tool (Aquatic Species Invasiveness Screening Kit) to provide an estimate of risk of invasiveness of marine waters of Florida. The established species was identified as a hazard and potential invasive. All other species scored well below the threshold for invasiveness and future climate had little effect on estimates of invasiveness. The analysis revealed little need for additional risk assessment or prohibitions on damselfishes in trade. Education, monitoring, and early detection and rapid response were the main risk management recommendations. The focused species selection process employed herein provided hazard identification and preliminary risk estimates for just 11 species, but collectively, they represent 40% by volume of fishes imported in the marine ornamental trade.

Managing invasive species with prevention and early-detection strategies can avert severe ecological and economic impacts. Horizon scanning, an evidence-based process combining risk screening and consensus building to identify threats, has become a valuable tool for prioritizing invasive species management and prevention. We assembled a working group of experts from academic, government, and nonprofit agencies and organizations, and conducted a multi-taxa horizon scan for Florida, USA, the first of its kind in North America. Our primary objectives were to identify high-risk species and their introduction pathways, to detail the magnitude and mechanism of potential impacts, and, more broadly, to demonstrate the utility of horizon scanning. As a means to facilitate future horizon scans, we document the process used to generate the list of taxa for screening. We evaluated 460 taxa for their potential to arrive, establish, and cause negative ecological and socioeconomic impacts, and identified 40 potential invaders, including alewife, zebra mussel, crab-eating macaque, and red swamp crayfish. Vertebrates and aquatic invertebrates posed the greatest invasion threat, over half of the high-risk taxa were omnivores, and there was high confidence in the scoring of high-risk taxa. Common arrival pathways were ballast water, biofouling of vessels, and escape from the pet/aquarium/horticulture trade. Competition, predation, and damage to agriculture/forestry/aquaculture were common impact mechanisms. We recommend full risk analysis for the high-risk taxa; increased surveillance at Florida's ports, state borders, and high-risk pathways; and periodic review and revision of the list. Few horizon scans detail the comprehensive methodology (including list-building), certainty estimates for all scoring categories and the final score, detailed pathways, and the magnitude and mechanism of impact. Providing this information can further inform prevention efforts and can be efficiently replicated in other regions. Moreover, harmonizing methodology can facilitate data sharing and enhance interpretation of results for stakeholders and the general public.

Pet abandonment is an important introduction vector for freshwater aquarium fishes, as unwanted pets become too large for tank dimensions and are released into the environment. Concerns over pet abandonment may be particularly important for the U.S. state of Florida, which exhibits abundant access to freshwater habitats and a climate more favorable to tropical aquarium fishes than other continental U.S. states. Numerous studies have examined the factors affecting establishment for non-native species, including the importance of propagule pressure and climate suitability. For freshwater aquarium species, maximum body size can increase pet abandonment because they grow too large for the tank dimensions (i.e., “tankbusters”). Thus, large maximum body size may increase propagule pressure due to intentional release. In addition to being introduced in sufficient numbers, a match between the thermal tolerance of a species and the thermal habitat is necessary for establishment. Several large-bodied catfishes are found in the aquarium trade, including the goonch Bagarius spp., redtail catfish Phractocephalus hemioliopterus , and tiger sorubim Pseudoplatystoma tigrinum . Here, we experimentally determined the chronic lethal minimum temperature (CLmin) for the three catfishes. CLMin estimates for these three species were higher than many other ornamental species, highest for the redtail catfish (14.3 °C), lower for the tiger sorubim (11.0 °C), and lowest (9.9 °C) for the goonch. Given these lethal temperatures, the distribution of redtail catfish would be limited to South Florida while the tiger sorubim and goonch could live, provided other habitat characteristics are suitable, up to ~28°N Latitude in Florida.