# Smells like rotten eggs! But not Hydrogen Sulphide?



## gilfish (Apr 27, 2007)

Hi everybody. I change about 50% of my water every 10-14 days. Yesterday I did the typical cleaning - vacuum, new water, scrub algae, rince ornaments, etc. Last night I started smelling a rotten eggy smell. This morning before work, I smelled it a little more. And just now when I got home, i could smell it right when I came in the front door. Yuck! The tank looks perfectly clear and beautiful as it always does the day after cleaning. Fish are happy, water crystal clear. Fish hungry and beggging for food. But what is that smell!?? Thanks!!


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## dug99 (Nov 7, 2007)

I don't know exactly what is causing the smell, but I searched Google found this post on another site, look about half way down the page. 


> What may have also greatly harmed them is I noticed you mentioned a "rotten egg" smell. This is due to anerobic bacteria conditions. These Anerobic bacteria live in oxygen-less enviroments. This can be un-vacummned gravel, that turns into so-called "bad spots" where even good bacteria can't even survive. Or even clogged and very dirty filters. Anerobic conditions are both good in bad. Good in that they do remove some nitrate but more so bad in that they release gases that smell like rotten eggs and is VERY toxic to fish. This is a serious problem and you must become the mystery solver to find out what could be the problem in causing anerobic conditions in your aquarium.


http://en.allexperts.com/q/Freshwater-Aquarium-3216/Fishes-dying-transferred.htm

Hope this helps...


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## JouteiMike (Oct 7, 2006)

Is the smell coming from the actual tank water, or the filter(s)? 

What are your water parameters for ammonia, nitrite, nitrate?

How long has the tank been set up? 

Try more frequent water changes, like ever week.


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## fish_4_all (Nov 13, 2006)

Flake food in the rims of the aquarium can cause a pretty nasty smell sometimes. As for hydrogen Sulfide, when you did the grtavel vac, did you see a lot of bubbles coming out the gravel? If you did, stir up the gravel really well and try to make sure every squre inch is stirred up. If the smell is that bad and it is hydrogen sulfide you need to make sure you vent the house and get it out as it can be toxic to even humans. 

It could be many other thing also. A leak in the filter to the carpet or floor. A dead fish that has not been found. The food rotting on the rim of the tank. Algae that has began to die above or below the waterline. Just do a really good once over of the tanks if you do not see the bubbles from the gravel.


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