Well I decided to take the yellow porites out of the tank and put it into a white bowl with the regular tank water. With a pipette from one of my ex-hagen test kits, i started sucking out the ones i could see but some of them were good clingers and was kinda tough to suck them out so I reversed my technique and started blowing them off with the pipette. OMG ... the big ones blew off and small baby ones blew off and medium ones blew off the porites.
After about 45 minutes, I had blown off 40-60 of these nudibranches on my porites. Some of the baby ones were so small, the fit into the polyp hole of the coral and it was looking disgusting with the number of floating little yellow bugs in this bowl. I began playing around with these guys and added fresh water to the bowl (without the porites of course). they still held their shapes and didn't curl up. I swished them around and the ones that had gripped the bottom of the bowl didn't let go. So I suspect that a freshwater dip probably wouldn't have gotten them off like flatworms. I left them in the white bowl for about 20 minutes and I noticed that they were leaching out the yellow pigment that they had "stolen" from the porites to camofloage themselves. Very very neat.
There were so many of these suckers that I am suprprised my porites was still doing relatively well. Now I will check on it again next week and do the same thing to see if anymore of them showed up.
But for anybody who owns porites, look at them closely to see if they have any of these nudibraches. They WILL be the same color as your porites regardless what color it is because they eat and display the pigment of your coral.