[KSFish]

Hi, I'm new to your forums and I'm just not sure where else to turn!

We have a 55 gallon freshwater tank. We kept 4 goldfish in it until we transferred them to our outdoor pond. We then cleaned out the tank and added some freshwater tropical fish. About a month ago after doing a cleaning and water change, we had a hydrogen sulfide problem and it killed all but 3 of our fish. Since then we haven't been brave enough to add any more fish. 3 days ago after a water change we again had a hydrogen sulfide problem and it killed another fish. My husband wants to completely give up and get rid of the tank. Any suggestions? What are we doing wrong? I don't want to kill any more fish or deal with the HS smell! Yuck!!!

 

[dave in Iliamna]

From what I have read Hydrogen Sulfide usually comes from a anarobic bacteria in your filter or gravel. So I guess check your filter and maybe try to vacuume your gravel well.

 

[KSFish]

thanks, we did both of those things. I'm hoping the problem goes away soon.

 

[Oldman]

When you do a gravel vac, be sure to plunge the gravel vac all the way to the bottom glass and let it really stir the gravel well. That will release any gas pockets to the bucket instead of to the tank water and will prevent the build of anaerobic pockets where H2S can develop. You may only be able to really clean part of the substrate well with each cleaning but over 2 or 3 water changes should be able to do a great job cleaning the substrate and stirring it well. I would be surprised to ever see a H2S problem once you have done this even once as long as you do a part of the tank's substrate with each water change.