Why does my tank smell like a rotting fish?

[MeAko]

My indoor pond actually kinda stinks up everytime I do a water change. Cause I do a weekly 50% and the water level goes down by a foot and a half and the walls start to excude this smell.

 

[mshill90]

My indoor pond actually kinda stinks up everytime I do a water change. Cause I do a weekly 50% and the water level goes down by a foot and a half and the walls start to excude this smell.

I have a 1,500 gallon indoor tank with KOI in it, and I do more than 50% water changes every month, and mine NEVER smells.

I do small water changes every week as well, and that never stinks either.

Maybe I am just lucky?

 

[mshill90]

My indoor pond actually kinda stinks up everytime I do a water change. Cause I do a weekly 50% and the water level goes down by a foot and a half and the walls start to excude this smell.

And actually, I bet I know why your tank smells when you do a water change... your liner/billboard is not flat. There are tons of creases/folds where anaerobic bacteria, food, and fish poop will sit in, and it will literally rot and pollute your water.

#1 rule in pond lining... NO CREASES/FOLDS.

 

[bomber]

My wife says our house smells like fish but I am use to it now. Soon your smell will not bother you but it will still be there

 

[mshill90]

My wife says our house smells like fish but I am use to it now. Soon your smell will not bother you but it will still be there

Like the actual animal fish, or like river/creek water?

I smell the occasional river-ish smell, but never actual fish.

 

[bomber]

river creek water but she calls it a fishy smell.

 

[MeAko]

And actually, I bet I know why your tank smells when you do a water change... your liner/billboard is not flat. There are tons of creases/folds where anaerobic bacteria, food, and fish poop will sit in, and it will literally rot and pollute your water.

#1 rule in pond lining... NO CREASES/FOLDS.

That's actually a good point. I do have a

That I use regularly to brush the sides and floor of the pond. I am a bit obsessive about places where filth hide and do believe I am relatively successful in cleaning crevices and folds, although I guess not as successful as I want to be...

Perhaps it might have something to do with the material of the liner? Do you have liner in your pond as well, if so, what type?

Okay, maybe I should've have said it "stinks", I guess it's a bit hyperbolic, maybe it has that river/creek smell, but definitely not odor-free, are you saying yours was odor-free? When the water level is not down though, it is odor-free. What kind of nitrates do you have in your koi pond?

 

[Krawnik]

Lastly, Krawnik although carbon normally isn't really needed in most tanks, to help possibly remove the smell a little quicker the carbon will definitely help the OP...

Agreed. However, "an ounce of prevention is worth a pound of cure".

 

[evbal]

I had the same problem in my 65G before.
then
1) Reduce fish amount
2) Keep wash filter floss every 2 days (Using AC110, AC70, Xp3)
3) Buy UV sterliizer

Problem gone

 

[SteveR]

My 75g has this scent coming off it like a rotting fish thats been left in the sun, I checked everything
Ph - 8.0
Nitrites - 0.20
Nitrates 0.50
Amonia 0.50
I even checked under all the rocks to make sure nothing got stuck there and died, I also checked the filter which smelled just as bad but it had nothing out of the ordinary in it (I still washed it anyway). My last water change was yesterday and I did a 25% change. It only started stinking like this is in the past 2-3 hours, what could be wrong?

I've not read this whole thread but every poster on the first page has failed to point out that amm should be 0 and the smell is ammonia! Obvious!