Dead rock anemone issue! Emergency, please help!

Hello! I woke up today to find that a missing rock anemone had died and nuked my 20 gallon nano reef! Both firefish gobies, clown fish, emerald crab, both urchins and hermits all dead! I only have 2 fish still alive and it's not looking good. I did a water change last night because the water looked a little cloudy. I didn't test it though. Today I did a 50% water change and added amquel plus to the water. I really don't know what else to do! I read online that rock anemones don't usually do that to a tank but it happened! I couldn't find it in there but the whole tank smells like dead fish. Is there anything else I can do?



Also I have been cycling my 55 gallon tank for about 2-3 weeks now. The ammonia is gone but nitrites and nitrates are present. Nitrites are at just under 2 ppm and nitrates are at about 10ppm. Should I move my living fish into that tank? Or is that just as dangerous?



My protein skimmer hasn't pulled anything out of the water since yesterday and I have a canister filter that is up to 40 gallons running in the 20 gallon tank. I have no other equipment in that tank. I have a deep 2-3 inch sand bed and 25 lbs of live rock. I pulled all the rock out searching for the dead rock anemone but couldn't find it anywhere. Someone please help! I need some good advice!



I got the rock anemone by mistake with an order I placed two weeks ago and I didn't want it but I didn't want to just flush it alive so I put it in my tank.. Huge mistake! I will never get one of those again..