The question is not if there is fragmentation. All file systems have some fragmentation.
The question is if the fragmentation is enough to affect performance.
On Linux file systems, fragmentation is typically less then 5%, often 1 or 2% unless the disk is 99% full. In the event of a full disk, you can see significant fragmentation, but in that case the problem is a full disk.
$ sudo fsck.ext2 -fn /dev/sda1
e2fsck 1.42 (29-Nov-2011)
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
Ubuntu_Rescue: 291595/1222992 files (**0.2% non-contiguous**), 1927790/4882432 blocks
So yes, there is 0.2 % fragmentation, but this is well below the 85% threshold to affect performance.
See the blog post Why doesn't Linux need defragmenting?.
On Windows, it is not uncommon to see 50% or higher rates of fragmentation (I have seen 200% plus). Thus windows needs defragmentation tools.
On Windows they advise defragmentation at thresholds of about 85%.
So, bottom line, defragmentation is not a large enough problem on Linux to affect performance, so there are no significant defragmentation tools and you are sort of wasting your time worrying about it.