Hope for the best. I've heard of others that have made it. Get some plastic canvas size 10 mesh and cover your powerheads. You can pick it up for less than $1.00 at any craft store. If you can't find any send me a pm and I'll send you a sheet.
Is the water cloudy? You could do a water change. I don't think it will harm your tank. Maybe check on the nano thread to see if someone there can tell you.
Run carbon if you havent already, get a water change ready and on hand. Test your water and keep a close eye on the animal. If it does die it will decay quick and smell really really bad. Sorry for your crisis in the future covering all power heads and intakes if you have an anemone is a must.
Some ideas... https://forums.saltwaterfish.com/t/305714/pre-filters
thanks guys i just hope he and the tank will be ok. i left this morning at 6:00 and i wont be back untill 5:00 tonight so i hope everything is ok!eastern time