Rotten Egg Smell

I've searched for some common causes but not sure if any of them fit my situation. Nothing obviously dead in my aquarium.

The smell seemed to come on really fast. Didn't notice it a few hours ago and now it's fairly strong.

40G FOWLR

Here's the things I've done recently.

Today:
Added another powerhead and pointed it at the surface.
Added 2 banggai cardinals
Noticed my anemone got caught in my hob but unplugged it and it seems to have come away with only a few crimped tentacles.

2 Weeks Ago:
Water Change
Added 15lb more live sand

Not sure if any of these things recently caused this but sure would like to get to the bottom of it.

 

I've heard that dead anemones smell horrible.

Something could have died outside your tank too. Have anything large that could have got out, like a turbo snail or a fish?

 

All fish are accounted for. Will spot all the snails and watch them for movement.

The anemone is still gripping the rock firmly so I don't think it's that. Here's a pic of its damage.

 

did you add the sand on top of your existing sand? Any black spots in the sand bed? If you can see under your tank, look under there and see if there are any black spots.

 

At some time you released a pocket of hydrogen sulfide. Running some new carbon usually helps with the odor.

You may want to watch for any signs of stress to fish or corals or a day or two.

 

Spread it over my existing sand. Some of it had become quite brown due to algae but there were no black patches. Cant see under the tank unfortunately.

Also, just got home and notice the smell has dissipated some. Everything in the tank seems to be functioning normally except for my angelfish. Usually swims circles around the tank all day long but he's been hiding in the place he sleeps. Maybe the new powerheads have scared him? I fed some flake and he still ate so that's good.


I'll do some water tests tomorrow and post the results.

 

Well my angel is on its side. I'm sure he will be gone by morning. All my other fish seem perfectly fine.

Was my favorite fish too.

 

Definitely the sand. You cannot do that with new sand. You just poisoned your tank. Any time you seriously disturb your sand this happens. Next time scoop a little sand away from a corner and pile the new sand in the corner. Slowly spread the new sand out over the period of a week or so.

You need to be doing lots of water changes.

Live and learn. I have done the same thing...

For future reference, any time you need to tear down a tank or seriously disturb a sandbed take all of the sand out of the tank and rinse it with freshwater until it is clean again. When anaerobic bacteria is exposed to oxygen or aerobic bacteria loses oxygen, it dies and smells like ****.

 

Sorry, no intervention that I can think of other than water changes helps with this situation. Hydrogen sulfide seems to be extremely toxic to marine fish and inverts, I know individuals that have wiped out their entire tanks.

Good luck to you and hopefully you will have just a small bout of the side effects.

 

Just did a 5 gal wc and checked all my levels. Everything is normal so I guess I'll just continue to do wc's and hopefully things will stabilize soon.

Amazingly my angel is still alive. His gills are going a mile a minute but he did manage to swim to the other side of the tank when I started doing the tests. None of my other fish se to be effected.