i think it is a bit bigger than three inches. when i took the pic w/ the ruler it was about 4 or 5 inches back so it makes it look smaller than it is. but that thing is huge. biggest one i have ever seen by far.

from what i have read and my experience they just filter stuff out of the water and if they cant get enough that way then they pick left over foods off the sub. and plantsprofessa19;2719617; said:nice job...do those clean your tank at all?
