Why Might My Fantails & Comets Keep Dying?

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daveo

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Hi guys

I'm new to fishkeeping and have a recurring problem with my fantails and comets dying. I'm looking for ideas on the possible cause...

I have a 30L (8 gallon) freshwater tank. The tank has 6 danios who have been in there for 6 months+ and are fine. At any one time I also have a single comet or fantail.

Every few months the comet or fantail dies. 4 deaths now. The symptoms seem to be the same - fins clamped for a day, hiding motionless at the bottom for a day, dies a day or two later.

The tank has been cycled and stable for 9 months. Every week I get identical results: Ph 7.6, Ammonia 0, Nitrites 0, Nitrates 10-20 (I can't tell which - the colour chart colours for 10 and 20 look identical on my API Freshwater Master Test Kit). Water temp about 21c (70f). There's some unplanted, live Brazilian waterweed in the tank.

I do 10L water changes every weekend and clean algae off the glass. Before adding the new water to the tank, I add 1.3ml API Stress Coat (left for 5 minutes before adding anything else), 0.6ml Seachem Flourish (for the waterweed) and 0.6ml Seachem Stability. I've tried both using and not using Aquarium Salt. The waterweed gets replaced when it stops looking bright and green.

The fish get fed daily with a few pinches of Aqua One Goldfish flakes. The danios are fast and greedy, but I always make sure the comet/fantail gets a flake or two.

My local aquarium expert has tested the water and agrees that the chemistry seems fine.

I'm stumped and beginning to feel guilty about replacing the victims. Any ideas on what it could be or what I could try?

This is Mavis. I'm hoping I can keep her alive and healthy for longer than Fantail, Zap, Oranges and Paris.

20180915_173245.jpg


Thanks!
Daveo, Melbourne, Australia.

One last detail I forgot to include: The tank has an under-gravel filter and built-in pump. It's an .
 
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kayla.s

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Goldfish need much bigger tanks than an 8g unfortunately. 30g is the minimum recommendation for a fancy goldfish whilst somewhere around 100g for comets as they get massive. Even fancies have the potential to grow to the size of a fist. The amount of ammonia goldfish produce is also extremely high (one of the reasons they need big tanks) so a mixture of stress and likely high ammonia in the water is what is killing them. Stress also leaves their immune systems weak and open to a bunch of other illnesses.
 

Discus-Tang

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Hey Dave! Nice to see another Aussie on the forum.

Most would agree that it would agree that it would be linked to the size of the tank & their need for a variety of foods.(Check out my article "The Importance of Variety" for more food info). A fully grown goldfish won't fit in a 30l tank.
 

daveo

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Goldfish need much bigger tanks than an 8g unfortunately. 30g is the minimum recommendation for a fancy goldfish whilst somewhere around 100g for comets as they get massive. Even fancies have the potential to grow to the size of a fist. The amount of ammonia goldfish produce is also extremely high (one of the reasons they need big tanks) so a mixture of stress and likely high ammonia in the water is what is killing them. Stress also leaves their immune systems weak and open to a bunch of other illnesses.
Hi, thanks for your advice. Surely, ammonia can't be the problem because my ammonia level is consistently testing as zero. Noted re the tank being too small for a grown fish. I've been buying 4cm comets/fantails so I assume they that the tank being too small won't cause them stress until they're larger?

Hey Dave! Nice to see another Aussie on the forum.

Most would agree that it would agree that it would be linked to the size of the tank & their need for a variety of foods.(Check out my article "The Importance of Variety" for more food info). A fully grown goldfish won't fit in a 30l tank.
Food variety is something I haven't thought of. I'll read your article, thank you. Am I right in thinking the size of the tank shouldn't be a factor at the moment since the comets/fantails have been about 4/5cm long when they've died?
 
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Discus-Tang

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Food variety is something I haven't thought of. I'll read your article, thank you. Am I right in thinking the size of the tank shouldn't be a factor at the moment since the comets/fantails have been about 4/5cm long when they've died?
I wouldn't rule it out.
 

daveo

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All this talk of stress is making me wonder about my barking puppy and screaming kids. Could a (relatively) noisy house routinely result in the death of goldfish? If so, my danios must be either deaf or very chilled out.
 

Discus-Tang

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It could be a contributing factor, but it's usually not the cause. Unless one of your kids screamed directly into the tank
 

daveo

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What about the strength of the water current? Could that be a factor?
 

Mcasella

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There is also a good chance in the small tank that the danios are taking the goldfish out due to lack of space (they can be nippy and won't do it all the time so if you aren't watching the tank for several hours at a time you could miss it, clamped fins could be stress or disease).
 

allllien

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You didn't mention using a water conditioner? What do you use to neutralize chlorine / chloramine etc?
 

daveo

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You didn't mention using a water conditioner? What do you use to neutralize chlorine / chloramine etc?
The API Stress Coat is the water conditioner.

There is also a good chance in the small tank that the danios are taking the goldfish out due to lack of space (they can be nippy and won't do it all the time so if you aren't watching the tank for several hours at a time you could miss it, clamped fins could be stress or disease).
Interesting. I certainly see them getting nippy when the fantail/comet gets sick. Although the first one that died was before I had the danios in there.

How much surface agitation is there? I'd say no, due to the floating plants you have in there.
I'm not sure how to describe it. The current is enough to push the floating plants to the front half of the tank.
 
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scarface

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I think it’s pretty pointless to be using Seachem Stability and aquarium salt.

Who knows what happened to the other goldfish. Perhaps they were sick already and symptons only showed much later. Good luck with Mavis. She looks healthy, so maybe the cycle of death and “rebirth” finally ends with her.
 

daveo

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I think it’s pretty pointless to be using Seachem Stability and aquarium salt.
Yeah, I think I'll stop with the Stability. I was also thinking of using Prime instead of the Stress Coat water conditioner.

Being new to all this, aquarium salt confuses me. It seems that 50% of people swear by it and 50% of people say not to use it. I've tried a few months with and a few months without. The fish died in both cases. My water does test a litle hard so I thought that might be a reason to use it?
 

Fawkes21

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Hmmm

Could be your previous fish were already sick with something?

That said the symptoms you describe of the fin clamping suggests stess/ammonia or nitrite poisoning.

I think that the too small tank combined with the big bioload of the goldfish plus the danios means your fish are probably dying as result of prolonged exposure to ammonia/nitrites.

Another culprit may be your filter. A risk with under gravel filters is that the gravel gets clogged up with fish waste, debris etc and reduces water flow/ filtration rate of your filter. This can to spikes in ammonia and nitrites.

The reduced water flow can also cause anaerobic bacteria to grow and these can be harmful. That could explain why your goldfish are dying, especially if combine that with the stress of living with nippy danios.



If I were you I would do a couple of water changes each week instead of one and get another filter, preferably one for a 60 litre fish tank and an internal filter or hob filter. I would also swap the stress coat for seachem prime as from experience I find it to be a better conditioner.

Hope this helps and hope Maevis pulls through, (apologies for the wall of text)
 

daveo

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your fish are probably dying as result of prolonged exposure to ammonia/.
I'll definitely look into replacing the filter, thank you. And I'll replace the Stress Coat with Prime.

Re prologonged ammonia/nitrites, how could this be given that I test the water every week and the tests show 0 for both every week?

An interesting theme that's come up from all of you good folk who are helping me here is the 'tank is way too small for a goldfish' one. I understand why this might be a problem when a fish gets bigger, but why might it be a problem when the fish is only 4cm long?
 

scarface

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Yeah, I think I'll stop with the Stability. I was also thinking of using Prime instead of the Stress Coat water conditioner.

Being new to all this, aquarium salt confuses me. It seems that 50% of people swear by it and 50% of people say not to use it. I've tried a few months with and a few months without. The fish died in both cases. My water does test a litle hard so I thought that might be a reason to use it?
Yes, I would stop adding salt. I don’t know if it caused your fish to die, but I do think you’re overcomplicating things.

I never heard of people adding salt to hard water. That’s news to me.
 
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