Fishy Weird – But True

Can you imagine Tropical fish in the Canadian Rocky Mountains at 4,800 feet? Well its true and they have a range, restricted to a small marsh fed by two hot springs on Sulphur Mountain in Banff National Park, Alberta.

Way back in the twenties a tropical fish was brought in to aid in the control of mosquitos. Then illegally some local aquarium enthusiasts introduced or dumped other tropical fish such as Sailfin Molly, Guppy, Green Swordtail, African Jewelfish, Convict Cichlid, and Freshwater Angelfish later. Only the Mollies and Jewelfish have persisted to today.

Several hot springs drain into this marsh below the Cave and Basin – Click Image for Larger View
Photo by J.Borno

Mosquitofish were introduced in 1924 for mosquito control. This aggressive fish, native to the south-eastern United States, is the most abundant in the marsh. Fertilization is internal. Within 16 to 28 days after mating, the female will give birth to about 60 young.

From the 1920s to 1950’s, mosquitofish were a major factor in the eradication of malaria in South America, in southern Russia and in Ukraine. The lifespan of a mosquitofish averages less than a year and the maximum is about 1.5 years.

Mosquitofish – Click Image for Larger View
Photo by J.Borno

Sailfin Molly is also native to the south-eastern United States. Look for these along the shoreline near the warm water inflows. The original mollies released were solid black. From these, chequered or marbled blacks, along with an occasional golden colour have evolved. The natural lifespan of sailfin mollies is short, particularly in the case of the males, which may live less than a year after achieving sexual maturity.

Naturally occurring populations of sailfin mollies also help to control mosquito populations by feeding on the larvae and pupae of these pests.

Tropical fish from the viewing platform – Click Image for Larger View
Photo by J.Borno

The Jewelfish is a rare sight in the marsh. The colourful fish native to Africa, turns a bright red during the breeding season. The African jewelfish is not a community fish. Because of their beauty many people desire them as pets. This fish is aggressive and preys on other fish.

The female will lay her eggs on a flat surface, will protect her eggs and kill anything that comes in close proximity. In a couple of days the eggs will hatch and the female will still protect them. The female can reproduce every three weeks. Jewel fish are 4 to 10 cm long.

Tropical Fish – Note the Banff Snails – Click Image for Larger View
Photo by J.Borno
The Banff Longnose Dace is a sucker like minnow that only lives in the marsh below the cave and basin. Specially adapted to warm water, it is now rare and endangered. It normally would only have spawned once a year and was out competed for food as well as the other exotic fish, preyed on its unhatched eggs.

In 1981 a research study showed that the habitat destruction and the introduction of the non-native fish threatened the dace. It is hypothesized that this Banff subspecies’ unique genetic structure was irreversibly mixed with another subspecies , and by 1986 it had disappeared and was declared extinct in 1987. Currently a study is underway to clarify the taxonomic classification of this putative subspecies.

Viewing Platform – Click for Map Location – Click Image for Larger View
Photo by J.Borno


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