I am amazed at how well this little guy cleared my whole tank of the red slime cr@p!!!! The sand that is. This stuff was out of control and I got sick of dumping the chemical junk in my tank so I thought I would givehim a try. Also my tank at work got the same problem not long after my home tank started. I got one for that tank too (little biocube) and the same result. Pretty cool, just thought I would like to share. This may be common knowledge to some, but I never heard of it until a buddy told me about it. Also the little goby is pretty cool and suppose to be semi aggressive, but he seems as mellow as can be.