Top off during secondary fermentation???

[photony]

I'm ready to rack my 6 gal muscadine batch from the primary into a carboy. While it's continuing to ferment in the carboy should I top it off yet or wait until fermentation is complete? Seems like I read that CO2 should protect it from oxygen problems as long as fermentation is taking place.

 

[Wade E]

Do not top up until fermentation has finished and has been stable typically at 1.000 or lower for 3 days or more.

 

[LtCellars]

What Wade said. The CO2 will protect your wine. As long as your airlock is in place you will be fine. When it looks like it has finished then check your SG. If you are going to do a MLF, and it's done with primary, now would be a good time to feed it the bacteria, top up and put the airlock back on.
Steve