Tank smells like rotten sushi

[Tomdavis331]

I recently acquired a 120gal setup with three Oscar fish and a sailfin placeo on offer up. Before filling the tank for the first time we drained it, cleaned the gravel substrate, and scrubbed the filter, pump, and and decorations. All the fish are alive and thriving. However, I have done two water changes in the last week due to the overwhelming odor that makes our room smell like a sushi restaurant. The smell came back a couple hours after the first and second water changes. What could the issue be and how do I correct it? We are first time fish owners and any help will be greatly appreciated. Thank you.

 

[Blue Demp]

Run it with carbon media. Say good bye to ordor

 

[Tomdavis331]

We’re rookies at keeping fish. Can you please explain what that is nd where to get it? Thank you.

 

[TwoHedWlf]

Sounds like you have an uncycled overstocked tank with large fish, overfed and underwater changed. Have you tested your water? It's normal to have a little bit of a fishy smell, but not a lot. You've a big bath of simmering rotting fish poo and food.

 

[Tomdavis331]

That’s what I thought. I’m thinking of doing a complete substrate change. There are only four fish in a 120gal tank. I wouldn’t think that’s over crowded?

 

[TwoHedWlf]

That’s what I thought. I’m thinking of doing a complete substrate change. There are only four fish in a 120gal tank. I wouldn’t think that’s over crowded?

Four BIG fish, it's not massively overstocked, but is overstocked.

Complete substrate change will probably just make things worse. Gravel vac it. And do more water changes.

Also test your water.

Also also, you don't have 3 oscars. You have 2 oscars, Jack Dempsey and a common plec.

 

[Tomdavis331]

Thanks for letting me know, I’m just going off what the dude told me who sold me the tank. It was disgusting with brown water and the filet was full of sludge. Just trying to give them a better home and not have my house smell like a sushi bar.

 

[tlindsey]

Carbon will only mask the problem agree with TwoHedWlf stated.

 

[burntrubber]

Do try filling up the tank. That's probably 30 gal of wasted space. If you need to reduce stock, get rid of the pleco. The 3 cichlids have probably worked something out already. I used to feed a local brand of sinking pellets, stinks up the water really quick so you might want to look into that as well.

 

[Fat Homer]

Okay, lets start with basics...

1. First thing i would do is look up what is known as the “Nitrogen Cycle in aquariums”, once you read that and get a basic grasp of whats going on you’ll have a better understanding on your tanks health...

2. Get yourself a Freshwater liquid master test kit by API from your local fish shop (LFS for short), and test your water to see what you are dealing with...

2a. If you dont want to test it yourself, you can bring a water sample to your LFS and see if they will test it for you... just make sure container is clean and contaminant free (this includes free of soap too)

3. Depending on what your water paramaters are like, you will probably need to do serveral water changes over the next few days or weeks till things balance out... this will also include sifting / stirring the substrate to remove organics trapped inside during water change...

4. Keep monitoring water parameters till everything is basically reading close to 0 except NitrAte which should read 1.0 or above normally after a week without water changes, then you’ll know your tank is more or less stable and the nitrogen cycle is working as intended...

5. From there, you will more than likely want to keep up with no less than 50% or more water changes per week which will include cleaning the substrate...

Then once all is said and done you should be able to enjoy some happy, healthy fish