[LuckyBlue]

Do I need to run a filter on a 6.6 gallon tank or can I just do water changes?

 

[wystearya]

You don't have to have a filter, but it makes it nice. A sponge filter is generally very quiet and doesn't disturb the water too much, if you decide to use a filter.

 

[LuckyBlue]

I don't know what a sponge filter is.... do you have a picture?

 

[wystearya]

I have this filter: http://www.amazon.com/Hydro-Sponge-...02S2/ref=sr_1_1?ie=UTF8&qid=1334522752&sr=8-1

And here is my 5 gallon tank with the filter in the back corner. You use an air pump to run the sponge filter.