Underwater Filter

Question
Is there such thing as an underwater filter for a fish tank? I'm placing my aquarium in a spot where the tank will fit, but it doesn't fit with the filter hanging out of it. Does a filter that goes underwater or doesn't add any additional clearance to the tank exist?

Thanks.

Answer
Gregg,
There is an under gravel filter, but I do not recommend them. They are more trouble than they are worth when it comes to doing your weekly gravel cleaning and water changes. You can get a filter that sits completely into the tank. I prefer the Whisper brand, but there are many of them on the market.