# My tank smells bad - how to fix it ?



## Idech (Nov 8, 2020)

My tank smells and I've done all I could think of to fix it. It just won't go away.

The tank is 48 x 18 x 21 (75 gallons) with 21 fish in it. Most Mbunas, medium size. None of the biggers one. All are around 10-12 months old. 75 lbs of Florida and lace rocks. Mostly Florida. One feeding a day, Northfin veggies and twice a week, spirulina Flaxes. 1 water change per week, 50%-60%. Sandbed vacuumed lightly one a week.
No algae, a little bit of diatoms but that phase is almost behind us. FX4 filter and Marineland Maxi-jet 1200 used as a polishing filter with polyfill changed every 7-10 days. FX4 maintained regularly. First maintenance (filter is new) was 1 month after setup and the sponges still relatively clean, as the Marineland picks up a lot. Water is crystal clear, but will get a little yellowish after a week, before maintenance.

I've had aquariums for many decades and it's the first time I've had a stinky one. It's ruining the pleasure of owning these fish and I'm seriously considering rehoming them all and continuing with a completely different setup. Putting my arms in there for maintenance feels like putting them in cat urine. I know my nose is more sensitive than most people's but that's just the way it is and I can't change that.

Parameters :
PH : 7.6
Ammonia : 0 or slight trace (0.10 ppm)
Nitrite : 0 ppm
Nitrates : less than 10 ppm
KH : 6-7
GH : 5-6 (not sure about this one, I don't remember)

Tap water is good quality city water. It doesn't have a bad smell. My saltwater tank doesn't smell bad and my previous freshwater tank didn't smell bad either.

Any ideas what is causing this ? I know carbon would fix this; I tried it. But it's just a patch and I don't want to keep using it.

Oh, and the fish went a few days without food while I was away and it didn't do much.

Any ideas ?

Thanks !


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## ironspider (Dec 5, 2017)

Maybe you have a dead fish in there under the rocks or something.

Activated Carbon will help with smells.


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## Idech (Nov 8, 2020)

ironspider said:


> Maybe you have a dead fish in there under the rocks or something.
> 
> Activated Carbon will help with smells.


I've had a dead fish in there before and it's a completely different smell. I know carbon would help but it won't fix the cause. If it's smelling bad because it's overstocked, then I don't think it should be kept as it is. Also, I've read carbon can be bad for cichlids. I don't remember why though.


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## Auballagh (Jan 29, 2003)

Long term use of Activated Carbon/Charcoal has been positively linked as a causal agent for HLLE (Hexamita outbreak - Head & Lateral Line Erosion) in New World Cichlids. There are some other problems as well, that c an also affect African species Cichlids as well. Not sure what those problems are. 
And yes, Activated Carbon/Charcoal would be a great, short term fix for the smell. I use the stuff to remove all traces of any medication after a water change. Long term use though, is probably a bad idea....
Got a few suggestions,
- Less fish. Yes, you know this already. And definitely be careful on this one, as balanced aggression in Mbuna groups can be upset with the loss of a few fish (possibly resulting in the loss of even more fish....). 
- More tank. A 150XH with sump filtration would give you an aquarium with a 2' X 4' 'footprint (same length as your 75G), if tank space is at a premium. Go high with the rocks (30" tall in those bad boyz) and you may have a winner.
- Install a dedicated, plant refugium. Pothos is one type that supposedly works great in immersed (not completely submerged) applications, and they look nice. I prefer the external, high mount overflow refugium type, that uses the tank sort of as it's sump. 
-
Those are three possible solutions, that I believe would work for you. I personally like the plant idea, because a well-planted refugium would definitely eat that stinky stuff out of your water pretty effectively. Plus, done right they look pretty nice as well. And lastly, the install may involve a bit less work, cost and overall effort than going with a much larger aquarium.


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## Deeda (Oct 12, 2012)

Can you describe the smell?

Have you checked the tank lid and under the rim for uneaten food? This is the usual culprit for smelly tanks.


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## Auballagh (Jan 29, 2003)

Oh, yeah....
-
_*A food pellet squished between the glass top and the tank rim.....*_
-
You're right Deeda.
Every time my own tanks smelled bad and it wasn't a dead fish... it was ALWAYS a trapped, food pellet caught up somewhere between the glass lid and the tank rim.
And yes, sometimes it really is the easiest solutions we overlook, when trying to fix these problems.


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## Idech (Nov 8, 2020)

@Deeda, the smell reminds me of urine in cat litter. I'm 100% sure there are no pellets caught anywhere because I always feed in the same spot, far from the glass top, and I also clean both sides of the glass top at least once or twice a month. I did it this week and there wasn't a single pellet. Good thinking though !

@Auballagh, thanks for the many ideas. They're all very good but unfortunately impractical for me. That leaves me with one option, less fish.

Here is what I have, and they are all working very well together. Not much aggression at all. The ones that seem less happy are the astatotilapia latifasciata, so I would choose them to go, plus another group, but not the demasoni if I can avoid it. They are all about 10-12 months old.

Labidochromis caeruleus : 1m:2f
Pseudotropheus demasoni (Pombo rocks) : 2m:2f
Pseudotropheus acei Ngara : 1m:2f
Labeotropheus fuelleborni OB (Chinyankwazi island) orange : 1m:2f
Cynotilapia sp. lion (Mara rock) : 1m:3f
Astatotilapia Latifasciata/zebra obliquidens (hap from Lake Victoria) : 4 (unknow sex, 1-2 males probably)
Total : 21 fish

Which would you keep ?

Thanks !


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## Deeda (Oct 12, 2012)

No cats in your house? That is a distinctive smell so just curious.

What water conditioner are you using? Prime smells more like sulfur.

Also just curious that you notice the tank water looks yellowish after a week despite your 50-60% water changes. I'm wondering if your tap water is high in dissolved iron, may want to check your local water report or see if they are adding anything during treatment for the summer months.

You mentioned you have/had a saltwater tank that doesn't smell. If you still have it, are you treating that water differently?


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## Auballagh (Jan 29, 2003)

Definitely roll down through 'Deeda's Troubleshooting Checklist'. Very thorough!
But.... 
If it doesn't work, and you really are committed to removing some fish? I would remove the Haps like you already indicated, plus the Labeotropheus fulleborni. Reason is that L. fulleborni get big, and I'm not sure 2 females is enough to hang in there long-term, with your male (my own L. fulleborni males were always these kind of obnoxious 'budfies', that liked to throw their weight around at just about everybody in the aquarium).


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## noddy (Nov 20, 2006)

The only time I smell anything like that is when I wipe the underside of the glass lids down.
There's usually a silvery looking build up that I assume is the same stuff that sits on top of the water if you don't have sufficient surface agitation. Protein.


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## Idech (Nov 8, 2020)

Deeda said:


> No cats in your house? That is a distinctive smell so just curious.
> 
> What water conditioner are you using? Prime smells more like sulfur.
> 
> ...


No cats, just two small dogs. I use Prime. I'm waiting to finish the bottle to never buy it again. I hate that stuff. But I used to have another conditioner that didn't smell before the Prime and the tank still smelled bad.

Dissolved irons, hmm, I really have no idea. But the smell is present all year round, not just summer. Right before this cichlid tank, I had a planted community tank and it smelled nice and fresh. So I really don't think it has to do with the water.

For my saltwater tank, I use RO/DI water that I make, so you can't compare.

Someone on another forum mentioned it might be what I feed. I've never heard of that but maybe it's possible ?


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## Idech (Nov 8, 2020)

Auballagh said:


> Definitely roll down through 'Deeda's Troubleshooting Checklist'. Very thorough!
> But....
> If it doesn't work, and you really are committed to removing some fish? I would remove the Haps like you already indicated, plus the Labeotropheus fulleborni. Reason is that L. fulleborni get big, and I'm not sure 2 females is enough to hang in there long-term, with your male (my own L. fulleborni males were always these kind of obnoxious 'budfies', that liked to throw their weight around at just about everybody in the aquarium).


I agree with the fuelleborni having to go. They will get big and the two females are constantly holding eggs. It can't be fun and I feel for them.

Then I would have 7 less fish, for a total of 14. Hopefully this would help with the smell. What I find strange though is that's the same number as some of the templates for a 75 gallons. And many people, I would say most people with african cichlids have about this number in their tank. Some even more. Why is only mine smelling bad ?


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## Idech (Nov 8, 2020)

noddy said:


> The only time I smell anything like that is when I wipe the underside of the glass lids down.
> There's usually a silvery looking build up that I assume is the same stuff that sits on top of the water if you don't have sufficient surface agitation. Protein.


The only thing I get under the glass lids is a little bit of green algae, on one side. And it easily wipes off. Algae has a distinct smell, but I don't find it's a bad smell. Also, the smell is really coming from the water. I wonder if I could have it analyzed in depth but professionals. To find what gives it this bad smell.


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## SenorStrum (Aug 14, 2020)

Cat Urine... that's the weird one here. I looked it up. The internet is actually in consensus on this one: Cat pee stinks!

But most of the smell from cat pee actually comes from Pheromones. But you mentioned that the smell was much more close to "Cat urine from a litter box." Cat urine in a litter box has already broken down. (Side note: Mammals excrete urea, not ammonia. Urea has no smell, it must be broken down by bacteria to ammonia to release the smell. This is why fresh cat urine smells so different from cat pee in a litter box that has been breaking down and smell like ammonia.)

I see that most folks have already gone down the dead-thing line of inquiry. I'm going to assume you didn't miss a dead fish  , but where did the rocks come from? Is it possible you accidentally gathered something that's not very inert and is breaking down in your tank? The fact that the water turns yellow and stinks basically is screaming that there's something in the system somewhere that shouldn't be. It's quite likely I'm wrong.

Water mold- I had a piece of driftwood which was too fresh in water once, and it grew water mold that smelled absolutely horrible. I have seen the same from YouTubers who put wood in biotope tanks. I've seen attempts at making these things get torn down because the smell never went away.

Plants - Auballagh is right that a heavily planted tank would get rid of the smells, but you can't do that with many fish. The O2 to CO2 trade off is too great. You'll kill something, plants or fish. I did have anubias root-rot go through my tank and kill a whole bunch of them. They smelled bad when you pulled them out, but did not color the water or make it stink.

The last thing I would poke is filtration. You say you maintain the FX4 regularly - how regularly, how much do you clean, an what is your primary bio-media? I find that a filter that gets cleaned too often will not work well. This is evidenced by the fact that you get any ammonia readings at all.

If you do have too many fish, it's too many fish for the filtration you're running. I don't believe you have enough fish to make your tank smell.


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## Idech (Nov 8, 2020)

SenorStrum said:


> I see that most folks have already gone down the dead-thing line of inquiry. I'm going to assume you didn't miss a dead fish  , but where did the rocks come from? Is it possible you accidentally gathered something that's not very inert and is breaking down in your tank? The fact that the water turns yellow and stinks basically is screaming that there's something in the system somewhere that shouldn't be. It's quite likely I'm wrong.
> 
> Water mold- I had a piece of driftwood which was too fresh in water once, and it grew water mold that smelled absolutely horrible. I have seen the same from YouTubers who put wood in biotope tanks. I've seen attempts at making these things get torn down because the smell never went away.
> 
> ...


Thanks for trying to help, I appreciate it.

About dead fish, the only think that could be possible is some of the fries died inside the rocks. But I really doubt it, I've never seen any that were alive, except one and it was 3-4 months ago and I've never seen it again. Also the smell has started really early on, maybe even before the fish started reproducing.

The rocks came from a cichlid store and they were all « brand new ». I had a lot of diatoms on it for most of the tank life. Maybe 6 months. It's has been practically gone for a month, maybe.

I wish I had wood mold in the tank, it would be an easy fix !

The FX4 is new, and I've done maintenance once, after 4 weeks. I rinsed the sponges in tank water but they were not very dirty at all, so I schedule my next maintenance 8 weeks later. I'm not there yet. The bio-media is from various sources : some came from my Fluval 407 (Fluval bio-media), some came from the FX4, and a small portion came from an old tank I have 10-15 years ago.

An FX4 and a Maxi-jet 1200 with filter floss should be enough for this size tank I hope. I see people with bigger fish and similar settings and they're not complaining of smell.

Sigh.


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