White mushroom hydra like stuff in aquarium?

[jelyfissh]

have anyone seen this growing in tank before, I have those little white mushroom like stuff growing in the tank recently, I dont know what exactly it is, I searched around the internet, maybe white algae? hydra?
If anyone had seen this before, plz give me some info, thank you so much!!!

 

[jwh]

If it's hydra, I find it grows in all my new set-ups, but disappears as the tank matures and the water parameters stabilize. If it occurs in an established setup your water management is suspect, increase WC, filtration, general maintainance of substrate and the tank as a whole.