Velvet
 

Well it looks like my fish were infected with velvet after I added some live rock from another hobbyist's tank. I managed to catch all the fish from the display tank, quarantine them, and treat them. My question is, if I fill the display tank back up with just freshwater for a week or so, will that kill whatever parasites were in there? The tank was fish only with recently cycled live rock so I realize that's all dead rock again, which is fine, but I want to make sure no parasites survive as well.

Theoretically, yes. Never tried it myself.

Also I think you can go fallow for some time too and velvet will die out

Yes but that's 3 months and I'd rather be certain. Is there any chance they can survive in freshwater at any stage in their cycle does anyone know?

3 months worked fine for me.

You had corals to care for though too. Since I don't, I'm just wondering if leaving freshwater in the tank for a week will do the job so I can start cycling again and hopefully don't have to wait another 3 months to re-add the fish.

Well, everything I know says yes, fresh water will kill it. anything that lives in SW will be affected by the osmotic difference of FW. In the case of protazoa, I would imagine very quickly.

Let's hope so. I just wish there was a way I could find out for sure.

can't velvet live through hypo ? I'm not sure but i thought it was resistance to that thats why people just do TT or copper and velvet doesn't get affected by hypo

Just hate to see you nuke your whole tank with FW if u dont have too