Why Did My Goldfish Die? Black spots on her face and body

HI everyone. Unfortunately, one of our fish (a yellow goldfish) died yesterday. We're not sure what happened, and were hoping some of you might know.

Basically we went away on holiday on Wednesday. Both fish were completely fine. We turned the light off, kept the filter on, and put in two holiday feeding pellets.

When we got back on Sunday, however, she had developed lots of black spots on her face and body. Her fins were also blackened along the spines. We put her into a quarantine tank, where she survived for another day. She then rolled over onto her side, moved around for a bit and died.

We're not sure why she developed all these black spots and blackened fins. Searching online, the likely culprit seems to be ammonia burns, but our other fish (an orange goldfish) is completely okay.

As far as I can tell, we did everything right: had an adequate sized tank with good filtration, carried out regular water changes, used bottled water (as our tap water isn't very good quality) with good pH levels, etc., treated the water every so often with Seachem Prime and allowed h good bacteria to grow. Plus, if the water is the problem, wouldn't it have affected our other fish as well? Could she have had a disease?

If it will help I can upload some pictures.

Thanks for your help!

 

Have you tested the water just in case?

 

Have you tested the water just in case?

Yes, we have done thanks (with Tetra test kits). The results were fine (as in, the colours were all in the recommended range).

 

Your first step in any and all fish related mishaps is water testing. Fish are no different than people, what kills one fast may take longer to kill another. We need your water parameters to better help. Ph, ammonia, nitrite and nitrate. What size is the tank? Was your tank properly cycled before adding fish. How regular are said water changes l, how much water are you changing. What does “every so often” mean in regards to your prime dosing?

Yes, we have done thanks (with Tetra test kits). The results were fine (as in, the colours were all in the recommended range).

That answer is inadequate. Ammonia and nitrite should be 0. Anything above 0 is harmful. Are you aware of the nitrogen cycle?

 

Your first step in any and all fish related mishaps is water testing. Fish are no different than people, what kills one fast may take longer to kill another. We need your water parameters to better help. Ph, ammonia, nitrite and nitrate. What size is the tank? Was your tank properly cycled before adding fish. How regular are said water changes l, how much water are you changing. What does “every so often” mean in regards to your prime dosing?

Nitrate read at 25 mg per litre, nitrite read at 1 mg per litre, pH read at under 7, ammonia read at 0 or trace amounts (we tested for ammonia using the apI kit, all the others using tetra). 30% water changes every week. For prime, we started out at once every day, then lowered it to two or three times a week. I'm not sure of the tank size in liters, but the dimensions are 16 cm (6 and a bit inches) by 34 cm (13 and a bit inches) by 30 cm (12 inches). The tank was cycled for over two weeks when we first got it.

 

Ok that helps. Your tank is not cycled, a cycled tank reads 0 ammonia 0 nitrite. I would triple test your water to ensure test accuracy. If those are your correct numbers than your tank is not cycled. With that being said you should be changing water every day. Your tank should also never not be dosed with prime while fish-in cycling. I cycled my 65 gallon with fish in it, I didn’t allow ammonia or nitrite to exceed .25 ppm. They would occasionally spike to about .5 but I would water change immediately. The tank was dosed with prime every single day. Low amounts of toxicity accompanied with prime gives your fish the least stressful situation possible. Also according to my calculations your tank is about 16 liters or about 4.3 gallons. How many fish are in your tank? I’m no goldfish expert but I know they’re known as “Dirty” fish, they produce a lot of waste. A stocking issue might be present here hopefully somebody else can chime in on. Goldfish in a small uncycled tank would be tough. A tank that size can have parameters fluctuate pretty rapidly. It’s beginning to sound like your ammonia burn diagnosis was pretty accurate. The ammonia could have spiked and dropped right back down in two days. Given your nitrite reading I think your ammonia went up high then your cycle progressed as what bacteria you do have converted that ammonia to nitrite.

 

Are you sure those are your tank dimensions? That is small even for a Nano Tank, a single betta is the only fish you could put in a tank like that (assuming 30x34 is the base and 16cm is the height. If it is the other way around, you cannot even keep a betta in there, only shrimp or snails). Whether your tank was cycled or not, such a small tank will lead to quickly fluctuating water quality. Even a tiny bit of waste may lead to significant levels of ammonia, nitrite, etc. in your water. Goldfish in particular are fish that need relatively large tanks for this reason.
Sorry about the loss of your fish. In all likelihood the holiday pellets actually contributed to water toxicity because in such a small tank, unless the goldfish ate every crumble, the dissolving food would rot and leech into your small body of water. Your other goldfish may have been lucky, or may have actually suffered internal damage from poisoning that you are not (yet) able to see. Vacuum your substrate, get your water back in order asap and upgrade your goldy to a larger tank in the future to prevent this malaise repeating itself.

 

Ok that helps. Your tank is not cycled, a cycled tank reads 0 ammonia 0 nitrite. I would triple test your water to ensure test accuracy. If those are your correct numbers than your tank is not cycled. With that being said you should be changing water every day. Your tank should also never not be dosed with prime while fish-in cycling. I cycled my 65 gallon with fish in it, I didn’t allow ammonia or nitrite to exceed .25 ppm. They would occasionally spike to about .5 but I would water change immediately. The tank was dosed with prime every single day. Low amounts of toxicity accompanied with prime gives your fish the least stressful situation possible. Also according to my calculations your tank is about 16 liters or about 4.3 gallons. How many fish are in your tank? I’m no goldfish expert but I know they’re known as “Dirty” fish, they produce a lot of waste. A stocking issue might be present here hopefully somebody else can chime in on. Goldfish in a small uncycled tank would be tough. A tank that size can have parameters fluctuate pretty rapidly. It’s beginning to sound like your ammonia burn diagnosis was pretty accurate. The ammonia could have spiked and dropped right back down in two days. Given your nitrite reading I think your ammonia went up high then your cycle progressed as what bacteria you do have converted that ammonia to nitrite.

Okay thanks, that's really helpful. I'll retest, then start carrying out daily water changes with daily prime. We only have the one fish in the tank now. On a separate issue, do fish do better in pairs (as in, should we get a second one to replace the one that died)? I've read mixed opinions on the subject. Also, I guess now he has the whole tank to himself.

 

If your tank is truly that small, you should rehome the goldfish you have now and maybe get a betta.

 

Are you sure those are your tank dimensions? That is small even for a Nano Tank, a single betta is the only fish you could put in a tank like that (assuming 30x34 is the base and 16cm is the height. If it is the other way around, you cannot even keep a betta in there, only shrimp or snails). Whether your tank was cycled or not, such a small tank will lead to quickly fluctuating water quality. Even a tiny bit of waste may lead to significant levels of ammonia, nitrite, etc. in your water. Goldfish in particular are fish that need relatively large tanks for this reason.
Sorry about the loss of your fish. In all likelihood the holiday pellets actually contributed to water toxicity because in such a small tank, unless the goldfish ate every crumble, the dissolving food would rot and leech into your small body of water. Your other goldfish may have been lucky, or may have actually suffered internal damage from poisoning that you are not (yet) able to see. Vacuum your substrate, get your water back in order asap and upgrade your goldy to a larger tank in the future to prevent this malaise repeating itself.

Yeah, the guy when we bought the tank said we'd need to upgrade in a year or so (this was about 3 months ago) when they grew bigger. At the time we just went with that, but I think we'll just go and buy a bigger one this weekend. Thanks for the advice.

 

Okay thanks, that's really helpful. I'll retest, then start carrying out daily water changes with daily prime. We only have the one fish in the tank now. On a separate issue, do fish do better in pairs (as in, should we get a second one to replace the one that died)? I've read mixed opinions on the subject. Also, I guess now he has the whole tank to himself.

I’ve only kept angelfish, Cory and neon tetra so I can’t really give quality advice on goldfish. However if the measurements you posted are accurate you should not replace the fish unless you can get a larger tank. Adding a fish back in during the cycle wouldn’t be a good idea anyway. No need to put anymore fish through the potentially fatal process. Just be diligent, you have to do what the beneficial bacteria your growing can’t do. My tank took 45 days to cycle, it was long.... and a ton of work. Some days 2 water changes were needed. Over the top water changes definitely slowed my cycle however every fish made it and never showed any noticeable signs of stress.

 

Okay thanks, that's really helpful. I'll retest, then start carrying out daily water changes with daily prime. We only have the one fish in the tank now. On a separate issue, do fish do better in pairs (as in, should we get a second one to replace the one that died)? I've read mixed opinions on the subject. Also, I guess now he has the whole tank to himself.

As you've said you are contemplating getting a bigger tank this weekend - that would be the single best thing for you to do now. Make sure to take some filter media from your cycled tank and put it in the filter of the new tank to help move cycling along faster.
20 Gallons is the recommended minimum for a single goldfish (= 76 Liters, you'll need something like a 70x40x30cm tank or 80x30x30). You can keep one goldfish by itself, no problem. Be aware though, that if you get an additional one, it is recommended to get another 10 gallons (~40 liters) per additional goldfish. So two goldfish would need 100+ Liters, which is pretty much a 1m tank (or 90cm if it has sufficient width). There are a lot of fish that can be kept (in large numbers) in much smaller tanks than goldfish, also flashy and brightly coloured ones, so if you are worried about space in your home you might want to trade in your goldfish for something else. If you do really want to keep your goldie, you should do some research. Fishlore's own species page on them is a good place to start.

I don't mean to come across as mean or anything, but taking the time to read up on future purchases really helps prevent disappointment and sad events like this. Also you cannot always trust advice from your local fish store. Whenever I find a new fish I'm interested in, I ask the seller for info, then exit the store and do some research online. Don't even trust the first article you read, take your time reading up on general info sites and topics on fishkeeping forums from people who have had them. If the online info is largely in agreement but the seller of the fish tells you something different (especially if it makes you more likely to buy it), you should be wary of that person's advice regarding other topics as well. I have access to about 7 different fish stores, I would only blindly trust advice from one of them (and then still I do my own research, no one know everything about every species).
Though you can keep fish in smaller tanks when they are juveniles, you need to be careful about the right moment to upgrade them (or they will experience stunted growth and stress). Moreover - actually most importantly - it is hard to keep a tank smaller than 10 gallons (= 38 liters) stable unless you already have plenty of experience. You might want to steer clear of nano tanks however attractive they may seem with their low cost and space saving dimensions. They are not good beginner aquariums.

 

I agree that the "holiday pellets" could have contributed to a spike in levels. Especially based on the timing of the death and the size of the tank. (For the record, fish can go a weekend without food...even a week or more)

But mostly....the tank size is your problem. You have two messy messy goldfish in a teeny tiny tank. Are you aware of how large goldfish get? I only ask because many people are not. If they are commons, they get almost as big as koi fish and really only belong in ponds.

Honestly, Your LFS very much mislead you by telling you that the goldfish could spend any amount of time in a tank that small. Let alone a "year or so"!! They would get extremely stunted. I think your tank is approx. 5 gallons based on the dimensions.

Two goldfish in a tank that small would make keeping the water quality in check very very difficult even in a well established cycled tank. You said you cycled it for 2 weeks. What does that mean?

Its great that you are planning to go out and get a bigger tank, but you need to go pretty big for it to be "adequate" size. And 20 gallons is not close to adequate for a common goldfish in my opinion. So I am not really sure why that is supposedly the recommended minimum as the previous post suggests. But I have heard that minimum suggested in the past.

I would suggest you try and get at least a 3 foot long tank if you can Or better yet....make a pond. lol.

 

Its great that you are planning to go out and get a bigger tank, but you need to go pretty big for it to be "adequate" size. And 20 gallons is not close to adequate for a common goldfish in my opinion. So I am not really sure why that is supposedly the recommended minimum as the previous post suggests. But I have heard that minimum suggested in the past.

It had actually not occurred to me that they might be commons, I was thinking veiltails or lionheads or the fancy like. I agree wholeheartedly with you.
(Edit: my standard is a bit distorted because they actually stopped selling commons as aquarium fish in my country years ago. You can only buy them as pond fish. They do have some of the smaller fancy breeds available for aquariums)

 

It had actually not occurred to me that they might be commons, I was thinking veiltails or lionheads or the fancy like. I agree wholeheartedly with you.

True. The OP never really specified if they were fancies or commons. I am simply making that assumption. Since they are more.....common (hehe see what I did there???)

You can only buy them as pond fish. They do have some of the smaller fancy breeds available for aquariums)

THAT IS AWESOME!!! I wish they would do that here too!! But no....they sell bowls and tiny tanks 5 gallons or less, with photos of goldfish on their box!! Encouraging folks to get them for tiny tanks.

 

THAT IS AWESOME!!! I wish they would do that here too!! But no....they sell bowls and tiny tanks 5 gallons or less, with photos of goldfish on their box!! Encouraging folks to get them for tiny tanks.

It is kind of off topic but maybe it helps the OP in relativising?
Yeah, this country is really progressive when it comes to animal rights, including fish wellbeing. All LFS have stickers on their tanks with the latin+common name of every fish species, minimum tank size (either length or liters) which is actually really accurate, PH/KH/GH ranges they prefer, temp, what they eat, if they're aggressive, schooling/shoaling/pair/solo, nocturnal and activity level. The smallest recommended tank size for any live fish is 40cm (16 inch) lengthwise, including betta. Also most stores no longer carry fishbowls, those that do have notes clarifying that these are not suitable for fish, only inverts. It is actually forbidden by law since some 5 years to keep goldfish in a bowl.
Yup. Things can be different if people are willing to make the effort! It also helps a lot that chain stores are a minority (Edit: this is not to say that I have not seen the odd LFS where things were ehh.. a bit different.)

 

After 20 years of keeping gold fish in too small a tank (I never new for the first 15 years) I have changed over to tropical fish. The first 15 years I had what is probably around an 8 gallon tank. The advice from the fish store when I first got it (I had two tiny black moors that were given as a novelty gift in a salad bowl) was that they would only grow to a size that was suitable for the tank (there may have been some truth to that, but effectively I guess you are stunting their growth).

That first tank was probably around 8 - 9 galons it was 18" long 12" wide and 10" tall (but not a rectangle, sort of a hex tank with two longer sides). Over the years I had some common commets, and some black moors and fan tails. They tended to live for five or so years. I did not know what the lifespan of a gold fish could be. The filtration was a fluval 2 which was about double the recommended size for the tank, the last 12 months or so of the small tank I changed to a fluval U2 which is rated for a 100L tank! .

About 5 years ago I found out just how inadequately small my tank was, and why It had been a struggle to keep the water quality in check. I bought a 90L (appox 24G) tank for my black moor, fantail and two commets. Definitely an upgrade for them, but from what I read now still too small. I still struggled with falling ph even with the larger tank volume, but some crushed coral in the filter fixed that. The main issue was nitrates, I think they were virtually never below about 80 (I was only doing 30% water changes fortnightly, and should probably have been doing at least 50% weekly). Five years down the track and the last of them passed on and I decided since I cannot really get a bigger tank I would change over to tropical fish, as it wasn't fair on the goldies to be keeping them in my small 90L tank.

So whilst it may seem possible to keep goldfish in a small tank, it will be a constant struggle, and the fish will not live anywhere near as long as they could naturally do. I've decided that goldfish are not the "easy" fish I originally thought they were, and that the tropical's (which I feared were much harder) are, provided you do adequate research, actually easier to look after.

I suspect that your use of the prime was protecting the fish with your cycle not being complete. From what I read it only locks up the ammonia for 48 hours, so most likely with you away for a few days and not dosing, that ammonia got released before your BB could deal with it.

Tony.