Thick mucusy water

Question
I changed my beta's water 7 days ago and the whole tank is foggy and filled with this thick mucus like substance. The mucus/slim is all across the top of tank and is about a half an inch thick. My fish sits in it and its like hes stuck in it.(he sits in it all day) What is it? I changed his water today( and it stunk real bad) and now hes swimming around again. His colour has faded alot. Whats wrong with him?

Answer
Hi Mandy,
  There is something seriously wrong with either your water or your fish tank, not your fish.  When you changed the water, did you use a gravel siphon to clean the gravel?   If not, you should.  Also, how large is the tank?   You should be doing regular partial water changes of 25% of the water once a week, every week to keep the tank happy and healthy.

-- Ron
  rcoleman@cichlidresearch.com
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