wow very cool article! i didn't know about freshwater sponges either. I don't have very many hydras, i think something eats them like my ghost shrimps, nymphs,planaria or leeches. since i have been placing lots of infusia for my larva ghost shrimps cyclop population has grown. are brine shrimp easy to maintain in a diverse envoriment? would love a flow up on the sponges