You may not have a good enough filter system, or maybe your filter is clogged and needs the filters changed. USually the cloudy elements are waste products from the fish as well as algae, etc. SOmetimes having a few sucker fish helps with the algae problem.

Hello; Not really enough information. Water should not be cloudy in an established tank. On a new tank --- increased bio-load, adding new fish etc. --- or something wrong with the filter, real dirty --- plugged --- or a cleaning that has killed of most of the beneficial bacteria the water will become cloudy as the bacteria that break down wastes multiply. The bacteria that break down the initial waste into ammonia double every 20-to-30 minutes --- the other bacteria that break down ammonia to nitrite and nitrite to nitrate only double once per 12-to-24 hours. So an increase in bio-load can cause a lot of problems if not done slowly! Start doing frequent water changes -- 5% to 10% a week and cleaning the substrate and filter media. There just may be a bloom of algae or micro-organisms that is clouding the water. Just about the time an aquarium cycles 6-weeks or so the nutrient build up of DOC's and nitrates etc. --- have finally risen to the point that algae will start to bloom. Usually a brown algae (diatoms) bloom and cover everything. This is normal and will go away and green algae will grow. Green algae is good for the whole system and fish will not stay healthy without some algae or green living plants to munch on very long. I do not change water of clean the substrate for the first month with a new tank --- I do clean the filter media every couple of days to remove excess waste as the bacteria load cannot break down the excess yet. Algae also removes DOC's (dissolved organic compounds)and nitrates along with phosphates that build up from feeding and may be present in your water supply. This is the main reason a new tank will not grow real plants for the first few months --- their is not enough food for the plants to grow. Look for the cause and remedy the situation. I hope it is just a bloom of diatom algae! OFM