What's new
By:
Filters

Cycled tank but fish dying

The October FOTM Contest Poll is open!
FishForums.net Fish of the Month
🏆 Click to vote! 🏆

J

JoeFinn1997

New Member
Joined
May 29, 2024
Messages
13
Reaction score
3
Location
England
Hello,

I’ve completed a fish in cycle (I didn’t realise this was bad due to poor advice from the store). My ammonia and nitrite readings are consistently 0 and my nitrates are kept below 50 with water changes when necessary.

However, it seems I am having more problems with fish health now the tank is cycled than while I was completing the fish in cycle. My fish are hiding a lot of the time, although still eating, and also I have lost two fish who seemed completely fine during the cycle and then went quickly downhill after the cycle.

I am just wondering what I can do to prevent further losses and is there anything further I need to check on the tank.

For reference, my tank is 100 litres and I originally had 8 Livebearers. 4 platy and 4 mollies. I have lost 1 of each fish so far. I only have artificial decorations and no live plantation.

From my understanding, the fish listed above are supposed to be ‘hardy’ fish. Therefore, if my main water parameters(ammonia, nitrite and nitrate) are consistently fine then I have no idea what is causing the issue. I have plenty of surface movement and also an air stone.

Any thoughts/advice would be much appreciated.

Thanks
 
The nitrates are high - aim for a maximum of 20ppm. Do you know/ can you test for the level of nitrates in the source water?
Platies and mollies need hard water - can you find the hardness of the water that you are using? Water companies usually publish this in the water quality report on their webpage.
What is your water change schedule and maintenance routine?
 
Naughts said:
The nitrates are high - aim for a maximum of 20ppm. Do you know/ can you test for the level of nitrates in the source water?
Platies and mollies need hard water - can you find the hardness of the water that you are using? Water companies usually publish this in the water quality report on their webpage.
What is your water change schedule and maintenance routine?
Click to expand...
I completed a water change this morning and the nitrates are reading as 5ppm as of just before my post.

I think my carbonate hardness is high but my “total hardness” is low. I have struggled with maintaining a high PH and i guess that may tie into the low total hardness?

If so, is there an easy way to increase the hardiness of the tank water and maintain that level?

In terms of water changes, I test the water every 3 days and complete a water change when I read high nitrates. I’ve been fasting the fish for one day a week and only feeding small amounts. I vacuum the fish waste during the water change also.
 
JoeFinn1997 said:
I completed a water change this morning and the nitrates are reading as 5ppm as of just before my post.
Click to expand...
Perfect.
JoeFinn1997 said:
I think my carbonate hardness is high but my “total hardness” is low. I have struggled with maintaining a high PH and i guess that may tie into the low total hardness?
Click to expand...
Are you referring to TDS (total dissolved solids) or GH (general hardness)? The GH needs to be around 200 for platies and 250ppm for mollies. Once you know your GH you could add mineral salts if necessary.

Meanwhile, post pictures of the fish and explain any symptoms in case there are other factors at play.
 
The easiest way to increase the GH, KH and pH is to add a Rift Lake water conditioner at a lower dose rate. You want the GH around 250ppm for mollies and around 200ppm for platies. Platies will be fine in harder water but mollies won't be ok in softer water so find out what the GH is and get it up to around 250ppm. A Rift Lake water conditioner will also raise the KH and pH. Mollies and platies like the pH above 7.0.

If you post pictures of the fish and 1 showing the entire tank, we might be able to offer more advice on what the problem is.

Naughts beat me to it :)
 
Just as an FYI

Hardening Your Water (Raising GH and/or KH)​

The following measurements are approximate; use a test kit to verify you've achieved the intended results. Note that if your water is extremely soft to begin with (1 degree KH or less), you may get a drastic change in pH as the buffer is added.
To raise both GH and KH simultaneously, add calcium carbonate(CaCO3). 1/2 teaspoon per 100 liters of water will increase both the KH and GH by about 1-2 dH. Alternatively, add some sea shells, coral,limestone, marble chips, etc. to your filter.

To raise the KH without raising the GH, add sodium bicarbonate(NaHCO3), commonly known as baking soda. 1/2 teaspoon per 100 Liters raises the KH by about 1 dH. Sodium bicarbonate drives the pH towards an equilibrium value of 8.2.

Raising and Lowering pH​

One can raise or lower pH by adding chemicals. Because of buffering, however, the process is difficult to get right. Increasing or decreasing the pH (in a stable way) actually involves changing the KH. The most common approach is to add a buffer (in the previous section) whose equilibrium holds the pH at the desired value.
Muriatic (hydrochloric) acid can be used to reduce pH. Note that the exact quantity needed depends on the water's buffering capacity.In effect, you add enough acid to use up all the buffering capacity.Once this has been done, decreasing the pH is easy. However, it should be noted that the resultant lower-pH water has much less KH buffering than it did before, making it more susceptible to pH swings when (for instance)nitrate levels rise. Warning: It goes without saying that acids are VERY dangerous! Do not use this approach unless you know what you are doing, and you should treat the water BEFORE adding it to the aquarium.

Products such as ``pH-Down'' are often based on a phosphoric acid buffer.Phosphoric acid tends to keep the pH at roughly 6.5, depending on how much you use.Unfortunately, use of phosphoric acid has the BIG side effect of raising the phosphate level in your tank, stimulating algae growth. It is difficult to control algae growth in a tank with elevated phosphate levels.The only advantage over hydrochloric acid is that pH will be somewhat better buffered at its lower value.
Click to expand...
from https://fins.actwin.com/mirror/begin-chem.html#altering
 
@JoeFinn1997 The most reliable way to find your hardness, or GH, is by looking on your water company's website. You need a number and the unit of measurement (there are several they could use). If you can't find it, tell us the name of your water company and we'll see if we can find the page.
 
Naughts said:
The nitrates are high - aim for a maximum of 20ppm. Do you know/ can you test for the level of nitrates in the source water?
Platies and mollies need hard water - can you find the hardness of the water that you are using? Water companies usually publish this in the water quality report on their webpage.
What is your water change schedule and maintenance routine?
Click to expand...
To say nitrates should be 20 max. What are you basing this on? And for what fish? All fish?
 
Last edited:
AJ356 said:
To say nitrates should be 20 max. What are you basing this on? And for what fish? All fish?
Click to expand...
High nitrate levels compromise the health and wellbeing of the fish. Their immune system is compromised and it can lead to disease. Nitrates should be kept as low as possible, preferably below 20 (although in the past it was thought that 40 was low enough, it is now thought to have a negative impact above 20). Some fish species are more sensitive than others. Most common causes can be easily controlled by good husbandry.
 
Essjay said:
@JoeFinn1997 The most reliable way to find your hardness, or GH, is by looking on your water company's website. You need a number and the unit of measurement (there are several they could use). If you can't find it, tell us the name of your water company and we'll see if we can find the page.
Click to expand...
United Utilities is the company. If you need further details please let me know.
 
JoeFinn1997 said:
United Utilities is the company. If you need further details please let me know.
Click to expand...
IMG_5424.png
 

Attachments

  • IMG_5425.png
    IMG_5425.png
    333.8 KB · Views: 22
Colin_T said:
The easiest way to increase the GH, KH and pH is to add a Rift Lake water conditioner at a lower dose rate. You want the GH around 250ppm for mollies and around 200ppm for platies. Platies will be fine in harder water but mollies won't be ok in softer water so find out what the GH is and get it up to around 250ppm. A Rift Lake water conditioner will also raise the KH and pH. Mollies and platies like the pH above 7.0.

If you post pictures of the fish and 1 showing the entire tank, we might be able to offer more advice on what the problem is.

Naughts beat me to it :)
Click to expand...
I’ve posted a picture of the fish tank below. I’ve also added details of the water company hardness in this thread as well.

Please let me know if you need any further details.
 

Attachments

  • IMG_5427.jpeg
    IMG_5427.jpeg
    349.1 KB · Views: 26
So your hardness is 5.04 Clark. This unit is not used in fish keeping, it converts to 4 dH and 72 ppm which are used in fish keeping.

You have soft water which is way too low for your fish - Colin gave you the minimum hardness for them
Colin_T said:
You want the GH around 250ppm for mollies and around 200ppm for platies. Platies will be fine in harder water but mollies won't be ok in softer water so find out what the GH is and get it up to around 250ppm.
Click to expand...


When hard water fish are kept in soft water they suffer calcium depletion and the stress of this leads to them becoming sick more easily. Colin also recommended using a Rift Lake conditioner to increase GH and KH to the levels needed by mollies in particular.
 
Essjay said:
So your hardness is 5.04 Clark. This unit is not used in fish keeping, it converts to 4 dH and 72 ppm which are used in fish keeping.

You have soft water which is way too low for your fish - Colin gave you the minimum hardness for them



When hard water fish are kept in soft water they suffer calcium depletion and the stress of this leads to them becoming sick more easily. Colin also recommended using a Rift Lake conditioner to increase GH and KH to the levels needed by mollies in particular.
Click to expand...
Thank you. So it’s the water hardness that could be causing the issues?

If so, I’ve seen the Rift Lake product but I can’t find it in the UK? Is there an alternative as I want to correct this asap

Thanks
 
A quick search on eBay and Amazon for "rift lake salts" and "cichlid lake salts" produces several products - Seachem Cichlid Lake Salt and Fritz Rift Lake Probiotic. The Seachem product just adds GH so you also need a separate buffer to increase KH. Though I don't know whether you would need their Tanganyika buffer or their Victoria/Malawi buffer - someone else should be able to help there. (Seachem also make an American Cichlid Salt, which is not the right one).

To use these, you would need to dissolve them in the new tank water at a water change before adding it to the tank. You would also need GH and KH testers so you know how much to add to get the level you need for the fish. You wouldn't need to test every time as once you know how much to add to each bucket of water just measure that same amount in future.



The other alternative would be to rehome the remaining fish and have soft water fish in the tank. A shop might be willing to part exchange your fish for soft water fish.
 
You must log in or register to reply here.

Similar threads

graceward
Recognizing Fishless and Aquarium Cycling
Replies
5
Views
281
sharkweek178
sharkweek178
F
Fish in Cycling
2
Replies
16
Views
255
Bamf Comics
B
R
Cycling - start again or be patient?
Replies
13
Views
365
Essjay
Essjay
K
First time cycling tank
Replies
7
Views
291
TwoTankAmin
TwoTankAmin
C
New tank, how to cycle
2
Replies
18
Views
445
Essjay
Essjay

Most reactions

Useful Links

Back
Top