Well technically inverts but live bodies none the same. Started my cycle back in Jan./18/14 And QT in Feb. Things finally came together this weekend and we bought a coral banded shrimp, fire shrimp, And a peppermint shrimp. Named them Rocky, Will, & scrat. Scrats that squirrel on Ice Age movie chasing that acorn all over creation. Did a water change as well , 17 gals. and my parameters stayed right on track. Awesome.