This tiny, near-microscopic water flea, daphnia-pulex, has more genes than humans. 

This freshwater zooplankton is the first crustacean to have its genome sequenced, and its 31,000 genes crowns it the animal with the most genes so far.  Humans have about 20,000 to 25,000 genes.

As well as having a massive number of genes, more than a third of them have never been seen before in other animals.

http://www.wired.com/wiredscience/2011/02/water-flea-genome/

http://www.newscientist.com/blogs/shortsharpscience/2011/02/diminutive-flea-packs-genetic.html