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

recently i bought a tank with bubble algae and some other kinda pest i left the LS in the tank for a night then i filed up the tank with fresh water for like a day now the LS is clean the bubble algae is gone from the LS all the worms all dead

Ya from what I've read, hyposalinity won't kill velvet but hyposalinity still involves a low salt level. Pure freshwater wouldn't include any salt which you would think would kill everything. I just hope it kills everything in all stages. It's too late about killing the live rock too. I've had the tank full of fresh RO water for a couple days now. The rock was cleaned with Bleach and Muriatic Acid before it was put in the tank so there wasn't much life on it anyways but at least it was cycled. I just don't want to put the fish back in there after 6-8 weeks only to find that velvet could survive in freshwater and have to start all over. Again.

i would add some Vinegar to the tank too if you are running FW this will drop the PH and hewlp kill off any other stuff.

Good call.