Cob Web like deposits

Question
QUESTION: Can you tell me what white cob web like deposits are on the inside of my tank of tropical fish. I am a complete novice and can't seem to find anything about it in books or library. A friend thought it may be angel fish spawning but I am not convinced.
Thank You
Carol Mclean

ANSWER: Hi Carol:  angelfish actually lay eggs that adhere to (usually) the glass wall of the aquarium or sometimes on a broad-leaf plant....so I doubt that it has anything to do with the angelfish...so let me ask you a few more questions... I am suspecting that it is some kind of fungus or uneaten food that has grown fungus.  So lets start with tank maintenance:  How often and what procedure do you use to clean your tank?  What is the tank temperature? How long have you been having this issue?  Are all of your fish accounted for?  Have you had your water tested?  Are any of the fish in the tank growing anything that may look like  white cotton or are any of your fish sick?  Lets start there so if you'd let me know the answers to these questions I'll try to give you a more definitive answer to your question... dave

---------- FOLLOW-UP ----------

QUESTION: This looks like white cob web type seposits on the glass with little lumps to the edges of it. I do a part water change (about 20%) once a week using a syphoning kit and treat the water I put in with water conditioner. Can't remember the tank temperature but it is within the range shown on the thermometer in the tank. I haven't had my water tested. How do I do this, what do I need? Fish all apear to be healthy enough no signs of cotton on them. Water has been treated with anti fungus and anti white spot treatments. Friend thought it might be angel fish because they seem to stick around the area where the deposits are on the glass.
Regards
Carol

Answer
Hi Carol:  I think you have an algae issue.  Just continue your normal maintenance and scrape off the cobweb-like-stuff.  If your fish are fine and showing no signs of sickness then I am almost certain it is algae.  The angelfish lay eggs so not sure what they would do to cause that.  Please keep an eye on both your fish and the algae and let me know if anything changes... dave