Red Shiner

The red shiner is a relatively small and deep-bodied freshwater minnow with adults ranging from 4.5 – 9cm in total length. Red shiners have a terminal mouth (mouth located in the front of the head pointing forward), a rounded snout, and a scaleless head oftentimes with a faint orange blotch present on the top surface just above its golden-yellow eye. The body is laterally compressed with colouration ranging from a shimmery blue/green. The dorsal surface of the body is darker in appearance while the belly resembles more of a pearly white. A distinctive trait of the red shiner is its vibrant orange-red coloured pectoral, anal and caudal fins, with the exception being the dorsal fin which varies from light to dark translucent grey (GLANSIS, 2021).

The red shiner is a particularly concerning invasive species due to its exceptional capacity to thrive in disturbed habitats with varying water qualities, quick reproduction, and potential to negatively impact native freshwater fishes. In aquatic habitats outside its native range, the red shiner displays aggressive and territorial behaviour, threatening native fish populations by competition for food and resources (MNRF, 2023). This invader also predates on the eggs of multiple native fishes, meaning that even fishes significantly larger in size could experience negative impacts or population declines. Aside from fish eggs, algae and plankton also make up a portion of this minnow’s diet. Algae and plankton play a vital role in the health of aquatic ecosystems. Algae improves water quality through the process of filtering and generating oxygen in the water. Plankton supports stable aquatic food chains and is a primary food source for countless native aquatic species. If these resources dwindled in large volumes, this could lead to population declines in native fish species and create excess sunlight penetration in waterbodies promoting the growth of toxic algae blooms. Additional possible consequences of the Red Shiner include the introduction of new diseases and pathogens, like Asian fish tapeworm, or even genetic impacts through hybridization (MNRF, 2023).

Outside of its native range, the red shiner has been documented in several American states, including most of the continental United States, and is especially abundant in urban streams in metropolitan Atlanta, Georgia (Invading Species Awareness Program, 2023). The red shiner is a habitat generalist and has little difficulty adapting to aquatic habitats with degraded water quality or limited resources. Currently, red shiner invasions have been reported only within the United States, outside of states where they occur naturally. To date, there have been no reports in Canada. Invasive distribution is believed to occur in 15 states, such as Alabama, Virginia, California, and Arizona (Invading Species Awareness Program, 2023). The spread of this invasive species into natural waterbodies has been facilitated primarily through intentional human releases. Possible examples of deliberate release may include pet dumping from aquariums or releases via bait bucket dumping.

As the red shiner has not yet been introduced anywhere in Canada, prevention is the most crucial strategy in ensuring this harmful species never becomes established. In Ontario, it is prohibited to possess, transport, release, buy, or sell members of prohibited invasive species, including Shiner. 

• If you possess a red shiner as an aquarium pet, contact the Invading Species Hotline at 1-800-563-7711 for further instruction.
• Never flush any aquarium pet down the toilet! This could facilitate its escape into natural environments or pass diseases to other native fish species whether they are alive or not.
• Never release red shiners into the wild.
• Never release the contents of a bait bucket back into any waterbody. In Ontario, it is illegal to deposit or release baitfish into or within 30 metres of any waters (including onto the ice).

If you think you have spotted or caught a red shiner, complete the following steps to report:

• Anywhere in Canada, you can report through EDDMapS at https://www.eddmaps.org/
  
  
• In Ontario, the Invading Species Hotline is 1-800-563-7711
  
  
• For other provincial resources, consult our Report a Sighting page