Powerhead Tar

I came home today to find my house smelling like gas, but my house is on electric only so it didn't make sense. I went upstairs and in the basement and it didn't smell in there, only the main floor. I went to check out my tank and all my coral and everything was closed up and the only fish out was the clownfish but he is usually in the anemone. I saw one of my power strips turned off so I turned it back on and my filters and powerheads started back up. I have some issues with my powerheads so I checked to make sure they were all working and all but one was. I took that one out and come to find out the propeller wasn't working because it was covered in black tar.
I smelt the tank and could tell the gas smell was coming from it.
I'm currently doing a water change and making more water. I took out the power head and got all the oil and tar off the top of the water with a net.

My tank is a 75 gallon with coral and 5 fish
I have two(2) 405 filters on it and a refugium on it. No skimmer but I plan on putting one on it tonight.
salinity - 1.025
ammonia - 0
nitrite - 0
nitrate - 40
ph - 8.0
phosphate - 0
calcium - 480

temperature is 78

the fish that I have: clownfish, 2 damsels, yellow angel, and a blue tang
I have seen all fish so far since taking out the powerhead but the blue tang
I have two anemones and they are both closed up
all the corals are softies and they have all been closed since I got home.

Other than changing out some of my filter media and doing a large water change, is there anything else I can be doing to help my tank fight through this? How worried should I be? I do not have a quarantine set-up so I cannot take anything out of this situation. My fish seem as though they are having trouble breathing, should I expect loss? Thank you for your time and advanced thank you's to anyone who can provide me some help or relief.

Just as I was writing this, one of the damsels died

Attached is a picture of what the tank usually looks like. The lights are currently off

 

well, both of the damsels died and so did the angel fish. The tang is still in the back but came out for a second and the clownfish went in the back as well. Im not sure if they are dead or still alive, and Im not sure when a good time is to start rearranging the rock to find them. Sad day

 

im sorry. what kind of powerhead was it? so the inner grease/oils escaped the pump? im guessing it was not a koralia. i would do many water changes. i hope your tank pulls through.

 

It was an Odyssea pump, and yes the oils escaped. I found my clown fish and he seems to be pulling through, and the anemones seem to be coming back as well. The only problem I'm finding is the water I'm making is way too cold to put in the tank, do you think I should put it in regardless or wait for it to warm up. I have heaters in the water I'm making. Also, its not fully aerated, should that be the least of my worries? I'm just a bit overwhelmed

 

Sorry for what happened! I fear similar situations daily myself. Waiting for the water to warm up a little is probably important for you right now. You don't want to stress everything more than it already is... I have heated cups of makeup water in the microwave and mixed with the larger batch in order to heat it up in a hurry. Good luck! I'm hoping you are able to save the majority of
Your livestock.

 

You need to get the temperature of the replacement water as close to the tank water as possible. If you put it in cold you will stress everything.
Use this method for the water changes - it'll bring down the contaminants faster than by doing partials water changes:
How to Reduce High Toxic Nitrates Quickly & Efficiently