Why Might My Fantails & Comets Keep Dying?

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.




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 .

 

Goldfish need much bigger tanks than an 8g unfortunately. 30 gallon is the minimum recommendation for a fancy goldfish whilst somewhere around 100 gallon 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.

 

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.

 

Goldfish need much bigger tanks than an 8g unfortunately. 30 gallon is the minimum recommendation for a fancy goldfish whilst somewhere around 100 gallon 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?

 

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.

 

I wouldn't rule it out.

Are they swimming around going, "Bugger, there's no way I'm going to fit in this when I'm older?!"

 

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.

 

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

 

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

 

How much surface agitation is there? I'd say no, due to the floating plants you have in there.

 

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).

 

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

 

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.

 

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.

 

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?

 

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)

 

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?

 

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.

 

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

Yeah, I think I may have been given a bum steer on this one.

 

A 4cm goldfish will become stunted in a small volume of water.

 

A 4cm goldfish will become stunted in a small volume of water.

I understand that. But until it's supposed to be bigger than 4cm, it won't be stressed right? It becomes stressed once it's supposed to be larger than it is. Is there a way to tell if a fish is 4cm because it's stunted vs 4cm because it has only just grown to that size? Perhaps I've been buying stunted fish from my local pet store (rather than just young fish).

 

I doubt that they are stunted at the store, they haven't been there for long.

I guess you're right. If 4cm is her size now, then she's probably not stressed, but she will grow quickly.

 

My two cents. The salt didn’t harm the goldfish without harming the danios and plants. If you test your water weekly you could still have spikes at some point during the week. Unlikely because sooner or later you’d be hitting the testing during a spike. Salt will soften hard water btw. As you can tell Daveo, I’m one of the “pro” salt users.
So, what happened to these guys? Question. How long did it take them to die in your tank? How long does it take you to acclimate them?
Danios can be pretty tough. And rough. They certainly can’t be ruled out. Especially if the Goldie is really small. And yes the tank will be too small. But that’s not what’s killing them right now.
So let’s all put our little minds together and make sure this little finbaby doesn’t end up dead too.

 

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?

Your tests results do seem fine but it still sounds like a water quality problem. I think a disease would have more symptoms like bloating, white spots etc. But that is indeed puzzling!

When do you test your water, before or after a water change?

Even small, goldfish produce a huge amount of waste. Space wise your tank is fine, it won't lead to stunting if you upgrade your fish tank eventually. The problem is that since goldfish produce so much waste, 30 litres is just too small a water volume to be able to cope with goldfish bioload without quickly becoming polluted.

As an example I had tiny baby pleco in a 20 litre tank. I wanted it to get bigger before I put it with my goldfish. I assumed a 20 litre tank would cope with a tiny 3cm pleco but he produced so much waste I couldn't keep the tank stable/clean so I transferred him to my main tank.

Sadly size is not commensurate to bioload, especially not with goldfish!

If you can, definitely upgrade your tank. It will be a lot easier to keep clean. That and goldfish grow very quickly. My ryukin went from 4cm to 8cm in about 10 months.

Just add, if you get another filter, transfer the media from the old filter into the new one or let the new one run alongside the old one until it develops enough good bacteria (or keep both) .

Hope this helps

 

Tell us more about the fish that died. Everything you can think of.

 

Goldies shouldn’t be living with Danios. Goldies should only be with goldies. Different needs totally. The danios are probably stressing the goldies to death and actually, it’s the danios that will pick at the goldies. They are simply NOT compatible tank mates. Good luck!

 

Goldies shouldn’t be living with Danios. Goldies should only be with goldies. Different needs totally. The danios are probably stressing the goldies to death and actually, it’s the danios that will pick at the goldies. They are simply NOT compatible tank mates. Good luck!

It’s still not adding up to me. Yes they could stress the goldfish out to the point of death. But there’d be signs of it before the dying. And for this many to have died one right after the other. Yes the danios could be stressing them but I’m thinking something with the water. Just too many have died. I’d still like to know how long after being added before they died. And the acclimation process.

 

It’s still not adding up to me. Yes they could stress the goldfish out to the point of death. But there’d be signs of it before the dying. And for this many to have died one right after the other. Yes the danios could be stressing them but I’m thinking something with the water. Just too many have died. I’d still like to know how long after being added before they died. And the acclimation process.

I actually have heard before long ago that tropical fish put off a chemical that can kill goldies. Gypsy, ever heard of this?

 

I actually have heard before long ago that tropical fish put off a chemical that can kill goldies. Gypsy, ever heard of this?

Never heard of that, but (zebra) danios are coldwater.

 

I actually have heard before long ago that tropical fish put off a chemical that can kill goldies. Gypsy, ever heard of this?

There are some tropical fish with toxins in their slime coat that could be harmful to goldfish. And catfish. Danios aren’t one of them though.

 

Salt will soften hard water btw.

Salt (sodium chloride) added directly to hard water won't soften it. Water softeners do use sodium chloride or potassium chloride but the mode of action is different as these softeners utilise a resin exchange medium to switch Ca2+ and Mg2+ with 2Na+ or 2K+.

It also depends on one's use of "hardness". General hardness, total hardness and permanent hardness measure water "hardness" by the concentration of divalent metal cations (mostly Ca2+ and Mg2+). As the sodium cation is monovalent when dissolved in water, it won't contribute to these measurements of hardness. However, TDS includes monovalent cations, so sodium will contribute to a greater TDS "hardness".

Some have raised ammonia/nitrite poisoning. I don't think this is the case. As the OP noted, his ammonia quite consistently tests under the detectable limit of his testing kit. It's true that ammonia can spike at times when not tested, mostly in response to feeding (ammonia excretion increases with elevated metabolism). But fish have a number of strategies that moderate the effects of localised ammonia pulses when feeding (Randall, 2002).

I think, perhaps, it's an issue of poor stock from whom the pet shop is sourcing their goldfish.

 

Salt (sodium chloride) added directly to hard water won't soften it. Water softeners do use sodium chloride or potassium chloride but the mode of action is different as these softeners utilise a resin exchange medium to switch Ca2+ and Mg2+ with 2Na+ or 2K+.

It also depends on one's use of "hardness". General hardness, total hardness and permanent hardness measure water "hardness" by the concentration of divalent metal cations (mostly Ca2+ and Mg2+). As the sodium cation is monovalent when dissolved in water, it won't contribute to these measurements of hardness. However, TDS includes monovalent cations, so sodium will contribute to a greater TDS "hardness".

Some have raised ammonia/nitrite poisoning. I don't think this is the case. As the OP noted, his ammonia quite consistently tests under the detectable limit of his testing kit. It's true that ammonia can spike at times when not tested, mostly in response to feeding (ammonia excretion increases with elevated metabolism). But fish have a number of strategies that moderate the effects of localised ammonia pulses when feeding (Randall, 2002).

I think, perhaps, it's an issue of poor stock from whom the pet shop is sourcing their goldfish.

Thank you. And I do apologize. I didn’t mean to say salt actually softens water. Appreciate the chemistry lesson though.
I’ve not heard back from the OP yet. Maybe he’ll have more information soon.

 

Appreciate the chemistry lesson though.

I find that, out of all the water parameters, I tend to get waylaid by "hardness" the most because the term, when used by itself, is fairly vague, and there's a variety of terminology and methods to measure hardness.

I've read of "permanent hardness" (for GH) and "temporary hardness" (substituting for KH) here at Fishlore; my local water authority uses "total hardness" (for GH) and "alkalinity" (substituting for KH). Adding onto that, TDS quantifies another measurement of "hardness".I think, to an extent, it reflects differences in regional terminology in the US compared to Australia, but also different industry practices: insofar as I've noticed, GH is used in aquariums but I've not noticed it used in any other industry, likewise aquaculture uses alkalinity while we use KH.

Another area of confusion is that "temporary hardness" is equivalent to "alkalinity" (sometimes referred to as "carbonate alkalinity") but - so far as I've read - these are not equivalent to KH unless the pH is under 8.5.

Adding further onto that is the use of ppm (or mg/l) because it can variously refer to ppm TDS or ppm CaCO3, and ppm (or mg/l) CaCO3 can refer to GH (or permanent/total hardness) as well alkalinity (or carbonate alkalinity/temporary hardness) and KH.

In my experience, at least, specifying the chemistry can sometimes help clarify what we mean by "hardness" to minimise confusion.

 

I find that, out of all the water parameters, I tend to get waylaid by "hardness" the most because the term, when used by itself, is fairly vague, and there's a variety of terminology and methods to measure hardness.

I've read of "permanent hardness" (for GH) and "temporary hardness" (substituting for KH) here at Fishlore; my local water authority uses "total hardness" (for GH) and "alkalinity" (substituting for KH). Adding onto that, TDS quantifies another measurement of "hardness".I think, to an extent, it reflects differences in regional terminology in the US compared to Australia, but also different industry practices: insofar as I've noticed, GH is used in aquariums but I've not noticed it used in any other industry, likewise aquaculture uses alkalinity while we use KH.

Another area of confusion is that "temporary hardness" is equivalent to "alkalinity" (sometimes referred to as "carbonate alkalinity") but - so far as I've read - these are not equivalent to KH unless the pH is under 8.5.

Adding further onto that is the use of ppm (or mg/l) because it can variously refer to ppm TDS or ppm CaCO3, and ppm (or mg/l) CaCO3 can refer to GH (or permanent/total hardness) as well alkalinity (or carbonate alkalinity/temporary hardness) and KH.

In my experience, at least, specifying the chemistry can sometimes help clarify what we mean by "hardness" to minimise confusion.

All of this is true. And I understand what you’re saying. But the majority of people asking for help want just that. Help. I’m more likely to listen to chemistry lessons in the article section of fishlore than on a help thread. I understand mentioning the different parameters. But I want to get the OP to answer simple questions. And I want to give simple answers. My only consideration is helping the OP help their fish.
I’ve not listened to any articles on the actual chemistry involved in water parameters for aquariums and ponds. When you’ve got time, perhaps you could check it out. If there’s none there you could write some. I think you’ve really got a good point in the differences between countries especially. I’m thinking it’d be an article I’d be glad to listen to.
In the meantime, I’m still waiting on the OP’s answers.

 

All of this is true. And I understand what you’re saying. But the majority of people asking for help want just that. Help. I’m more likely to listen to chemistry lessons in the article section of fishlore than on a help thread.

Please don't take my posts as a criticism, and for what it's worth, I heartily agree with your posts re: the benefits of salt as a prophylactic and that it's very unlikely to have affected the goldfish negatively.

I mainly included the explanation on hardness as a benefit to the OP as I noticed that he's in Australia: I thought he might be confused (as I was) by the different expressions of hardness, especially as used in Australia compared to the US.

 

Please don't take my posts as a criticism, and for what it's worth, I heartily agree with your posts re: the benefits of salt as a prophylactic and that it's very unlikely to have affected the goldfish negatively.

I mainly included the explanation on hardness as a benefit to the OP as I noticed that he's in Australia: I thought he might be confused (as I was) by the different expressions of hardness, especially as used in Australia compared to the US.

I understand. But I’m serious about the article. I think it would be beneficial.

 

I understand that. But until it's supposed to be bigger than 4cm, it won't be stressed right? It becomes stressed once it's supposed to be larger than it is. Is there a way to tell if a fish is 4cm because it's stunted vs 4cm because it has only just grown to that size? Perhaps I've been buying stunted fish from my local pet store (rather than just young fish).

A stunted fish will usually have out of propertion eyes

 

Let’s get back to issue at hand. I have always disliked chemistry and could care less about it. Never worried about PH, hard water or soft water and my fish thrive. Thank goodness! Lol

 

Sorry I thought API stress coat was more for stress / slime coat, didn't realize they have a water conditioner one, it's probably good but I know some of the older types don't always remove all heavy metals etc, I had some problems with that in the past.
I use Seachem Prime now and haven't had a problem since, you could try it but it still may not help.

 

A stunted fish will usually have out of propertion eyes

I've never noticed that, but with livebearers they look the same except developed / sexually mature (eg. you see a gonopodium on what looks like a juvenile). Anyway, a stunted fish will normally just be small, not unhealthy.