Starting fresh

[KDB]

I had lost all my fish to velvet (last fish died on July 18)
I have been running my tank with nothing in it, at a high temp to kill off everything.
I did a few vacuums, and some tank cleaning, but I noticed the algae was growing.. so I added some Microbial culture, that was given to me at the fish store.
I used bright well aquatics. I followed instructions, but I didn't notice these little white spikey balls until I entered it into the tank.
are these safe?
I am looking at reintroducing fish in the tank soon. I finally found a seller who will quarantine the fish for me! yay.

 

[Timfish]

Those are Tethys spp sponges. Harmless, they show up in all my tanks sooner or later. If you watch them they will s-l-o-w-l-y move by stretching or shortening the threads they attach themselves with. Can get up to roughly 1" in diameter.

 

[thatone08]

Those are actually pretty cool looking!

 

[davidcalgary29]

I had lost all my fish to velvet (last fish died on July 18)
I have been running my tank with nothing in it, at a high temp to kill off everything.

Just remember that high temperatures won't really help you with eliminating velvet from your tank. You need to keep your tank fallow for a minimum of six weeks, although, if it was a bad outbreak of ich, there is some limited data that 72 days may be required instead.

 

[lxxnp1234]

are they soft? they could be sponges.