Final answer:
Signs of sludge and water in the tank are likely caused by the presence of organic matter, such as decaying plants or animals. Organic matter can lead to the growth of algae and other microorganisms, resulting in sludge and water contamination. Different fish species in tanks can also affect the accumulation of dissolved organic carbon and the occurrence of algal blooms.
Step-by-step explanation:
Signs of sludge and water in the tank are likely caused by the presence of organic matter, such as decaying plants or animals.
This organic matter can lead to the growth of algae and other microorganisms, resulting in the formation of sludge and water contamination.
In the case of fish tanks, the presence of two-species fish can contribute to the accumulation of larger particles of dissolved organic carbon (DOC), blocking sunlight and preventing algal blooms.
In contrast, tanks with single-species fish may contain smaller DOC particles, allowing more sunlight penetration and promoting algal blooms.
It is important to regularly clean and maintain the tank to prevent the accumulation of sludge and water contamination. Proper filtration and monitoring of water quality can also help prevent these issues.