Oh no!!! :( Those are the worst kind of flatworms. Ime I have seen many types of flatworms but those were the first I ever experienced having a reef. They are a much brighter orange than the average flatworm. I got them in my first ever reef, a 10gallon. I did not use flatworm exit and actually have never had success using that product when using it on other flatworm populations. Also if you kill them in the same tank as your corals the toxins from their dead bodies will harm your ecosystem if their are many of them.
Talking about many of them... it looks like your getting some carpeting already... it will get worse, eventually imagine the carpet you walk on, nothing but flatworms. They are parasitic in that they will perch on anything that can give them more light and block the light from your photosynthesizing reef creatures.
You can increase your flow and that will deter them from carpeting but thats not a real solution. I don't know about fish solutions but I did successfully eliminate them from my first reef. I set up 3 temp acclimated freshwater baths and a new clean tank. Dip in first bath and shake like hell for 30 secs then the next and then the 3rd. The key is to shake each piece of your tank off. The flatworms will fall off and die in the freshwater. Get rid of your sand or clean it thoroughly too, basically everything in your entire tank.
Its a serious procedure but it worked for me and I never saw them again... now I quarantine and hate them. But not all flatworms are bad, just those bright orange rusty ones, they carpet everything and are parasitic!
good luck man,
Kris
