Goldfish filter, swimming against the tide ^^?

Question:

I put the filter 1cm under the water as instructed and the cloudyness is going slowly but the fish seem to be pushed slightly i turned it as far down as possible any ideas would be great.

Answers:

is the filter under gravel,or on the back of tank if under gravel the air pump is to strong if back filter it is to big, you need to correct the problem because it will pull the slime off the fish making prone to disease