What might have killed my goldfish?

[Yarkii]

Hello all.

I was recently given someone else's goldfish tank (without the fish or water). It was just a little 20L tank and came with the filter & filter media, light, gravel & an ornament. I didn't know then that it was way too small for goldfish, and I didn't know about cycling tanks. (I can hear you shuddering already. I feel so guilty.)

My local aquarium gave me loads and loads of what I now believe to be extremely bad advice. This included saying we could have three goldfish in there. We didn't, but I now realise that we shouldn't have even had one (we had two for about a week). We didn't cycle the tank, but the API '5 in 1' Test Strip readings were consistently NO3 0-20, NO2 0-0.5, pH 6.5, KH 40, GH >=180. We were given the impression by the LFS that that meant it was already cycled.

Long and sad story short, three fish met their sad ends in that tank, within a matter of a couple of months. I've learnt just how bad that LFS is, and won't be going there ever again. I do however want to use this tank as a quarantine tank for a much larger new tank (220L) that is currently one week into a fishless cycle. However, I'm rather scared to use this tank for a QT, in case there are parasites in there that killed the previous fish.

I don't know whether to throw out the gravel & filter media, clean out the glass tank & the filter, purchase new gravel & filter media (or maybe a whole new filter) and start cycling it as a brand new tank, or whether there is some way to confidently and thoroughly treat it for all possible parasites, then cycle it again (do you do that?), before safely setting it up as a QT for the bigger tank. I'd like to have as similar as possible an environment in both tanks, so I'm leaning towards throwing everything out and starting from scratch, but as you've realised by now I know extremely little about fish keeping, and just don't know how to decide what to do.

I don't know what the three fish died of, but they all slowed down in their activity for a number of days, and swam rather oddly towards the end. The last poor fish kept getting stuck in the plants, then when I got him free he'd be pushed around by the flow of the filter (it wasn't that strong). He'd sometimes try to swim straight up but fall vertically backwards. He'd sometimes move forwards but twirl around and around like he was on a fast-rotating spit. Sometimes he'd hang around the bottom of the tank, and sometimes (not often) he'd float a little lop-sided. In the last two days he most floated. I couldn't see any unusual colorings or spots or growths or bulges or anything else like that on any of the fish, to my uneducated eye. They all ate the floating fish flakes that the LFS sold me when I bought the first goldfish.

I feel extremely guilty sharing this information on here. I tried to look after these fish, and trusted the LFS, but now know we should never, ever have had goldfish in that tiny little tank.

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[SnailPocalypse]

Ok your goldfish died as of not cycling your tank before you got them so the ammonia was still toxic which is what killed them as if you do cycle with fish you must do water changes and have a filter.Next is that tank is way overstocked If I am correct I believe it is 1 goldfish for every 55 gallons?Someone else with have to confirm that one.Also test strips are not that accurate I reccomend you get a API master test kit which is way more accurate.

 

[Yarkii]

Thanks SnailPocalypse. I now know it was overstocked even with one goldfish, and that the LFS were wrong in saying it didn't need to be cycled. I did weekly water changes and tested the water daily (I didn't have an ammonia test though - just the 5-in-1 test strips).

So I never tested for ammonia, but the NO3 & NO2 readings were always 0 or just over (those API test strips are a little hard to read). After the first two goldfish died, the LFS tested my water. I assume they tested ammonia, but they never told me what they tested. They immediately gave me a replacement goldfish, so I assumed the water parameters were okay.

Is this what happens to goldfish when they're subjected to toxic ammonia levels (the slowing down and odd swimming)?



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[Hefin's Aquatics]

Hiya! I've been keeping fish for 20+years and my family have also:
Cycling doesn't take up to 6 weeks (like some say) it actually depends on the size of the tank so your tank (20 litre) would take 6/7 days to cycle fully. We've also kept goldfish in the past in a 5 gallon tank. (4 of them) and they survived no problem at all for 17 years! So I don't know what people are suggesting here. The goldfish also grew to their full length no stunting signs at all. But the problem is what caused your fish to die was the ammonia and they like PH at around 6.7-7.2. They also like temperatures between 18o.c (64o.F) and 22o.c (72o.F). They aren't actually cold water fish they are 'temperate' that's why me and my family kept them for 17 years without problem. However I'm sorry for your loss of goldfish, and I hope my advice helped you and that I hope to continue helping you in future if necessary.

 

[Yarkii]

Ok your goldfish died as of not cycling your tank before you got them so the ammonia was still toxic which is what killed them as if you do cycle with fish you must do water changes and have a filter.Next is that tank is way overstocked If I am correct I believe it is 1 goldfish for every 55 gallons?Someone else with have to confirm that one.Also test strips are not that accurate I reccomend you get a API master test kit which is way more accurate.

After reading your reply, I tested the ammonia (I've now got the API Freshwater Master Test Kit). It's reading 0 ammonia. Goldie died four days ago. I've kept the filter & lights going, but haven't done a water change since the night before he died (he died overnight, right after a water change). Would/could ammonia have dropped to zero in four days if it was ammonia that killed him? Could it be that there was/is enough bacteria to reduce toxic levels of ammonia to zero in four days once a pooping goldfish is removed, but not enough to stop the levels from being toxic while the goldfish was in there?

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[SnailPocalypse]

If all levels are zero (ammonia,nitrate,nitrite) it means cycling has not yet begun if ammonia rose then went back down to zero that would have to mean that nitrite was starting to form and eat the bacteria.Which means your tank has begun the cycle.Please give me a full set of tank parameters.

 

[Yarkii]

If all levels are zero (ammonia,nitrate,nitrite) it means cycling has not yet begun if ammonia rose then went back down to zero that would have to mean that nitrite was starting to form and eat the bacteria.Which means your tank has begun the cycle.Please give me a full set of tank parameters.

Do you mean you'd like to see the record of all the water parameters, or the readings as they stand today? They were always consistently within the ranges:

NO3 0-20
NO2 0-0.5
pH 6.0-7.0
KH 0-40
GH 180+

I just noticed there was one day where the NO3 was between 20-40, right after I put some seashells in on the advice of the LFS to try to raise the pH.

The day before Goldie died overnight, the readings were:

NO3 0
NO2 0
pH 7.0
KH 40
GH 180+

These were always measured with the API 5in1 Test Strips. Water temperature was usually around 21 or 22 during the day. I didn't look overnight. I never measured ammonia, until last night, when it was zero.

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[Yarkii]

Hiya! I've been keeping fish for 20+years and my family have also:
Cycling doesn't take up to 6 weeks (like some say) it actually depends on the size of the tank so your tank (20 litre) would take 6/7 days to cycle fully. We've also kept goldfish in the past in a 5 gallon tank. (4 of them) and they survived no problem at all for 17 years! So I don't know what people are suggesting here. The goldfish also grew to their full length no stunting signs at all. But the problem is what caused your fish to die was the ammonia and they like PH at around 6.7-7.2. They also like temperatures between 18o.c (64o.F) and 22o.c (72o.F). They aren't actually cold water fish they are 'temperate' that's why me and my family kept them for 17 years without problem. However I'm sorry for your loss of goldfish, and I hope my advice helped you and that I hope to continue helping you in future if necessary.

Thanks Hefin.

One thing I've quickly noticed in fish keeping is the incredibly varied range of advice I'll get depending on who I ask. I'm still in the process of working out which people/places/stores I prefer. For some of the issues, some advice is completely in opposition to other advice, and I've decided to go the way that sounds most logical and find out for myself. But there are so very many intricacies with fish keeping, and I'm an absolute beginner, so I have to keep searching, reading, asking and listening to everyone else's experience.

With my goldfish tank, the water was always around 21C or 22C that I noticed (I didn't look often). I struggled to raise the pH in the short time we had goldfish. Melbourne water is very, very soft, and many people seem to use blue crystals that (I only know this through observation) raise the GH significantly, raise the KH, but didn't seem to do much about the pH that I saw.

I just don't know if the tank cycled quickly or not at all. I let it run without a fish for a week or two before getting the first goldfish, but I didn't add ammonia or anything as I didn't know about doing that. It was a second hand tank, and the gravel & filter media had been in the tank for however long the previous owner had it, but it was given to me dry.

There was one goldfish in there pooping away, and for a short time two goldfish. I never measured ammonia, and the API test strips I used were quite frustrating & subjective to read, but NO3 & NO2 never got past the lowest two indicators (except on one day when NO3 was somewhere between 20 & 40).

I just don't know.

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[SnailPocalypse]

Take the seashells out they won't help and may harm your fish.As for Hefins advice.It is wrong.Go to any form and ask "can goldfish be in a 20 litre tank and mostly everyone (except the uneducated, don't mean it in a harmful way.) will say no.It seems you will need some ammonia to cycle your aquarium.You can order some on Amazon if you need.Otherwise do not put goldfish in there and cycle the. Tank

 

[StevenF]

I just saw your post about test kits earlier this month and replied to it. I won't repeat my entire post but I will say that I have compared Tetra 6 in 1 test steps against very good test equipment and test solutions of a known concentration. The tetra 6 in 1 strips are accurate. If you want to see what I use look at your other post on test kits.

Do you mean you'd like to see the record of all the water parameters, or the readings as they stand today? They were always consistently within the ranges:

NO3 0-20
NO2 0-0.5
pH 6.0-7.0
KH 0-40
GH 180+

The nitrite is high and the general consensuas is that it should be kept at zero. This indicates your tank may not be fully cycled.

Cycling doesn't take up to 6 weeks (like some say) it actually depends on the size of the tank so your tank (20 litre) would take 6/7 days to cycle fully.

How long it takes the tank to cycle is mainly determined by whats is in your tap water. Many people that have come to this forum have need 3 weeks or more to get the tank to cycle. Short cycles (one week or less) are rare. in only one case did I see evidence of a cycle only taking a day or two. If you try and cycle a tank with just RO water, it will not cycle at all For RO water it is best to fertilizer with a complete fertilizer mixed in with the RO water and ammonia. Even then it is not fast.

So your tank likely had ammonia recently. Hopefully you fish will recover. Don't feel guilty. What you have goon through happens to most people joining the forum. You have taken step to prevent these problems from happening again which is very good.

You can reuse your current gravel and filter if you want to. If you are concerned about parasites in it sterilize them with either a iodine solution or you can use a pure bleach solution to insure nothing is alive in it before it is reused. two tablespoons of iodine or bleach should be enough to quickly serialize everything in a tank. After that rinse everything out thoroughly and then you can start cycling the small tank.

Any plants you buy for the large tank should if possible go into the small tank first to insure any parasites they carry are gone before they are added to the larger tank. One month in the small tank without fish or snails should be enough time to starve out most parasites. It also gives you a change to check the pants for pests such as hydra or pond snails. And if you find these you can take steps to elliinate them before added the plants to the larger aquarium.

I always recommend having some crushed coral or natural sea shells in an aquarium to maintain minimum safe GH and KH levels for the animals (distilled or RO water is too soft for fish, shrimp or snails. Also it will neutralize any acids that may develope in the tank and help keep your water at a stable PH of about 7.

 

[Yarkii]

Take the seashells out they won't help and may harm your fish.As for Hefins advice.It is wrong.Go to any form and ask "can goldfish be in a 20 litre tank and mostly everyone (except the uneducated, don't mean it in a harmful way.) will say no.It seems you will need some ammonia to cycle your aquarium.You can order some on Amazon if you need.Otherwise do not put goldfish in there and cycle the. Tank

Thank you. Yes, I won't be keeping goldfish ever again. I've got some household ammonia that I bought to cycle the 220L tank. I'll use it when I start to cycle this tank too.

 

[Yarkii]

The nitrite is high and the general consensuas is that it should be kept at zero. This indicates your tank may not be fully cycled.

Thank you. I did always have trouble reading the strips, and deciding whether it was zero or just over zero. I mostly recorded '0-20' because I just couldn't tell. However, I realise now that no matter what, I am going to cycle this tank properly shortly.

If you try and cycle a tank with just RO water, it will not cycle at all For RO water it is best to fertilizer with a complete fertilizer mixed in with the RO water and ammonia.

I can't quite work out from the list of acronyms what RO water actually means.

You can reuse your current gravel and filter if you want to. If you are concerned about parasites in it sterilize them with either a iodine solution or you can use a pure bleach solution to insure nothing is alive in it before it is reused. two tablespoons of iodine or bleach should be enough to quickly serialize everything in a tank. After that rinse everything out thoroughly and then you can start cycling the small tank.

Thank you. I've been wanting to find out what will confidently clean any potential parasites. Also, should I discard the plants currently in that tank, in case there are parasite on them? They obviously won't survive bleaching, lol. There aren't many plants in there.

Any plants you buy for the large tank should if possible go into the small tank first to insure any parasites they carry are gone before they are added to the larger tank. One month in the small tank without fish or snails should be enough time to starve out most parasites. It also gives you a change to check the pants for pests such as hydra or pond snails. And if you find these you can take steps to elliinate them before added the plants to the larger aquarium.

I've already made the mistake, in my excitement, of buying plants and driftwood and putting them straight into the 220L tank, and then discovering little horn-something snails in the tank. Woops.

I always recommend having some crushed coral or natural sea shells in an aquarium to maintain minimum safe GH and KH levels for the animals (distilled or RO water is too soft for fish, shrimp or snails. Also it will neutralize any acids that may develope in the tank and help keep your water at a stable PH of about 7.

On Byron's advice, I've used aragonite as the substrate (and coral sand against Byron's advice because of the silica - sorry Byron), to raise the GH, KH & pH, as Melbourne water is extremely soft. There's 10kg of aragonite and 20kg of coral sand. So far it is sending everything up, but the GH needs to go higher and the pH might have gone too high. I don't know how high the KH needs to be (I aim to keep livebearers). I have read that driftwood can bring the pH down again (I assume it doesn't affect the GH, only because no-one seems to have mentioned it).

In my limited experience with the ill-fated second-hand goldfish tank, I noticed that the blue crystals the LFS supplied raise the GH very significantly but not the pH, so it has crossed my mind whether I should use these crystals in the big tank. However, I don't know what the blue crystals are made of. As this goes on, even with aragonite & coral sand substrate, I might need to find an additional way to raise the GH further without affecting the pH. Any advice to achieve that end would be appreciated.

EDIT: I think I'm getting my posts mixed up. The aragonite & coral sand (and plants, driftwood & unexpected snails) are in the new 220L that is currently cycling. I just realised that you probably mentioned the aragonite & coral sand as a suggestion to include with this tank once I clean it and am ready to start cycling it & setting it up.

 

[GobyMaster11276]

RO means reverse osmosis. And I believe you mean ramshorn snails? Good luck. They'll never go away. And I know how it feels to have that soft Melbourne water.

 

[fluttermoth]

Hiya! I've been keeping fish for 20+years and my family have also:
Cycling doesn't take up to 6 weeks (like some say) it actually depends on the size of the tank so your tank (20 litre) would take 6/7 days to cycle fully. We've also kept goldfish in the past in a 5 gallon tank. (4 of them) and they survived no problem at all for 17 years! So I don't know what people are suggesting here. The goldfish also grew to their full length no stunting signs at all. But the problem is what caused your fish to die was the ammonia and they like PH at around 6.7-7.2. They also like temperatures between 18o.c (64o.F) and 22o.c (72o.F). They aren't actually cold water fish they are 'temperate' that's why me and my family kept them for 17 years without problem. However I'm sorry for your loss of goldfish, and I hope my advice helped you and that I hope to continue helping you in future if necessary.

I'm sorry to disagree with you, but I'm afraid some of your information is just plain wrong

Your goldfish can't possibly have grown to full size in a 5 gallon tank. Normal, single tailed, common or comet goldfish should grow to around a foot long; fancies, like fantails or orandas, get to between six and eight inches in length. Four full grown goldies would not even be able to turn around in a 20l tank.

Length of cycling time is not predicated on tank size. There are so many factors that can vary that it's impossible to give time scales for cycling, whatever size the tank is.

 

[Hefin's Aquatics]

Well they survived for 17 yrs anyways so yeah