Eutrophic lakes, ponds, or rivers have high levels of nutrients in the water. This means that there are plenty of nutrients for plant, algae, and animal growth. They usually have turbid (cloudy) water because of the quantities of suspended phyto- and zooplankton, lots of plants and algae, and lots of fish and other animals. Also, because of high levels of plant and animal growth, eutrophic lakes tend to have lots of organic matter on the bottom, making them mucky. Very high levels of plant and algae growth often means that oxygen in the water becomes depleted, and that can kill the animals.