Goldfish and Water Temperature

Goldfish and Water Temperature Goldfish and Water Temperature The subject of my observation is a goldfish that is kept in a 2 gallon fishbowl positioned on a window side table. I have noticed that the goldfish is more active in the earlier morning and later evening than during the afternoon hours. Because the table is near a window that faces northeast, the fishbowl receives direct sunlight during the time between eleven o’clock a.m. and four o’clock p.m. The goldfish activity decreases around noon and remains lower until approximately six o’clock p.m. There are no filters or aeration devices needed in this smaller fishbowl since proper aeration is achieved by having an adequate top opening on the bowl, and also by the circulation of water achieved by the goldfishes swimming movements. (Fossweb) The water is kept at room temperature which is regulated by a thermostat set at 68˚F, which is within the recommended range of 64˚F-75˚F. (Cheng) Water in this temperature range holds more oxygen in solution than warmer water. (Fossweb) Why is the goldfish less active after the sunlight has been shining through the window up until shortly after the sun no longer reaches the fishbowl? The sunlight is solar energy and the glass fishbowl, being clear, is absorbing it causing the water temperature to rise. The water is gradually warmed by the sunlight, and the warmer water holds less oxygen in solution. (Biello) Since the sunlight only affects the water temperature for a limited time, the water goes through periods of heating and cooling. When the water is warmer, it holds less oxygen for the goldfish to breathe, so the goldfish may be struggling for air and less active. When the water cools, more oxygen is available for the goldfish to breathe, creating less of a struggle for the goldfish to breathe and remain more active. I would predict that if I were to move the fishbowl away from the daytime sunlight, then the water would remain at a consistent temperature

References: Biello, D. (2008) Fishing for Oxygen in Warming Oceans, May 2, 2008, Scientific American, http://www.scientificamerican.com/article.cfm?id=fishing-for-oxygen-in-warming-oceans Cheng, Ah (2008, April 1). List of Coldwater Fish for Aquariums and their Care. Retrieved July 22, 2009, from Fishkeepingtalk.com Web site: http://www.fishkeepingtalk.com/2008/04/list-of-coldwater-fish-for-aquariums.html (2009, March 31). Lawrence Hall of Science. Retrieved July 22, 2009, from FossWeb Web site: http://lawrencehallofscience.org/foss/fossweb/teachers/materials/plantanimal/goldfish.html (2008). Lenntech. Retrieved July 22, 2009, from why oxygen dissolved in water is important Web site: http://www.lenntech.com/why_the_oxygen_dissolved_is_important.htm