What is the gel substance which coats left over fish food?

There is a transparent gelly like substance coating left over food and poo and later on it floats to the top and then the matter inside drops but then the gel will float on top what is it lol BTW its a 180 gallon tank which had been cycling for a month and 3 weeks. I doubt its normal cause i never had this problem with my other 2 tanks should i just siphon it out or leave it if its being decayed i wont mind cause it will be filter out but if its harmful then its a problem so please leave answers and thanks for your time : P