According to the Virginia Department of Game and Inland Fisheries, pond fish may die for a number of reasons, including low levels of dissolved oxygen, pollutants, disease, temperature extremes or natural causes. The department explains that when fish in a pond begin to die or languish, it is imperative for pond managers to review these common factors to ensure that they are within recommended parameters. Often, the conditions causing the problem can be corrected.
According to the Warnell School of Forestry Resources, a division of the University of Georgia, Athens, oxygen depletion is a result of demand outstripping the pond’s supply. While the micro organisms and fish in the pond consume oxygen, the only organisms that produce oxygen are the plants. Additionally, the movement of air over the water can increase the amount of dissolved oxygen in the pond. Frequently, according to the Warnell School of Forestry Resources, fish kills occur during the summer, when pond managers overstock the pond or treat it with weed-killing chemicals -- both of which may reduce the available oxygen.
Outdoor Alabama cautions pond managers to be observant for the signs of low dissolved oxygen in ponds, such as fish swimming near the surface or gulping air. Usually, the largest fish die first.Learn More
According to The Goldfish Tank, goldfish in the right environment can live for many years in spite of their reputation for not having a long lifespan. Goldfish-as-Pets.com explains that the leading cause of death in goldfish is poor water quality, which is often caused by overfeeding that results in the build-up of uneaten food.Full Answer >
For live-bearing fish, the pregnancy length depends on the species of fish and varies considerably. For instance, according to the MCH Portal, platies have a gestation period of up to 7 weeks. On the other hand, mollies have pregnancies of about 4 weeks, according to Fish Lore.Full Answer >
Fish swim to the top of the water line in order to search for oxygen if the oxygen content in the water is too low. If pet fish are doing this, it usually means that they are in distress and are not finding sufficient amounts of oxygen in their own environment.Full Answer >
A frantically swimming fish is likely experiencing significant stress. Other stress symptoms include hitting the bottom of the tank, locking its fins to its side, and rubbing itself on gravel or rocks.Full Answer >