What is this?

[Jax1108]

Yesterday we noticed these tiny growths in our Betta's tank (looks like tiny ghost dandelions!) an also this fuzzy looking stuff. This past weekend we had a hell of a time, because his 6gal sprung a leak, replaced it with an identical tank which also started leaking so just decided to get him a 10 gal. When we removed the water, we saved about half of the tank water from his 6 gal to put in the 10gal. Is it algae? Is the flow too low?