Fish dying

[SJX]

Hi! I really need some advice, almost 2 weeks ago I upgraded for a bigger tank, I used the old gravel & water from my old tank and transferred it into my new tank so only the filter was new. All fish seemed fine so a few days later I added some platys ( I know I probably should have waited longer) anyway all was fine until Sunday when I noticed one of my molly fish had a really bloated belly then died that night since then all my harlequins have died one by one with no obvious reason, this morning my baby molly fish has also died with no obvious reason. I’ve tested my water multiple times at different fish shops and my water is perfect. I’m very worried about losing anymore fish. My Betta will not stop hiding which isn’t like him at all, there’s also a lot more aggression in my tank. Some fish have nipped fins and fin rot I think as cloudy white bits on fins so I’ve been usuing fit rot and fungus treatment however I do not think this is what is killing the fish. Please can someone help, I’m not looking for judgement so please ignore if your going to. Thank you

 

[foxgirl158]

May we please have your exact parameters?(Ammonia, nitrite, ect.) this helps us rule out any issues with the parameters.
How hard is your water and how high is your pH?

 

[foxgirl158]

May we please have your exact parameters?(Ammonia, nitrite, ect.) this helps us rule out any issues with the parameters.
How hard is your water and how high is your pH?

Also, is the betta in the same tank as the mollys, platies, and harlequins?

 

[SJX]

Also, is the betta in the same tank as the mollys, platies, and harlequins?

Sorry I don’t know what they are now as it was my husband who went but I went to 3 shops, 2 did test strips and 1 did proper testing but said it was fine and yes all in the same tank.

 

[foxgirl158]

Sorry I don’t know what they are now as it was my husband who went but I went to 3 shops, 2 did test strips and 1 did proper testing but said it was fine and yes all in the same tank.

My first piece of advice is to invest in a good water testing kit. Lots of people use this one, and it’s very simple to use. This will help you keep your water parameters in check, and also save time and gas by not having to drive to pet stores to get it checked every week


My second piece of advice is to get a separate tank (at least 5g, but bigger is always better) for the betta. Bettas are not community fish. They are not called Siamese Fighting Fish for no reason. It very well might be attacking the other fish during the night, or when you are not watching the tank. If you get a separate tank for the betta, please make sure it’s cycled.
Bettas and harlequins are also soft water fish, while platies and mollys are hardwater fish, which is why it’s important to know what your hardness and pH is. I believe this can be found on your water supplier’s website.

 

[Essjay]

Unfortunately many shops say things are fine when they are not fine. For example, anything above zero for ammonia and nitrite is not fine. When getting the water tested at a shop always make them write down the numbers.

I used the old gravel & water from my old tank and transferred it into my new tank so only the filter was new

This could be the problem. While the gravel will contain bacteria if the old tank had been running for years, if it had not been running long nearly all the bacteria would have been in the old filter. Using a new filter meant losing a lot of the bacteria so the tank is now trying to grow a lot more. Having your own test kit, preferably a liquid one, means you can test as soon as the fish start behaving oddly and see if there's a problem.
I suggest you get the tank water tested as soon as you can and get the numbers this time. The important ones are ammonia and nitrite - and as strips don't include ammonia, if the shop uses a strip make sure they also do an ammonia test. Once you have the results you'll know if ammonia and/or nitrite is the problem and if it is the "cure" is daily water changes until they remain at zero. In fact I would do a large water change without waiting for the results, just in case. A water change won't harm things but it could help. But take a sample of water for testing before changing the water.


foxgirl makes a good point about hardness. In West Sussex I would expect your water to be hard, but your water company's website should confirm this. If you can't find hardness on the website, tell us the name of the water company and we'll see if we can find it.

 

[SJX]

My first piece of advice is to invest in a good water testing kit. Lots of people use this one, and it’s very simple to use. This will help you keep your water parameters in check, and also save time and gas by not having to drive to pet stores to get it checked every week


My second piece of advice is to get a separate tank (at least 5g, but bigger is always better) for the betta. Bettas are not community fish. They are not called Siamese Fighting Fish for no reason. It very well might be attacking the other fish during the night, or when you are not watching the tank. If you get a separate tank for the betta, please make sure it’s cycled.
Bettas and harlequins are also soft water fish, while platies and mollys are hardwater fish, which is why it’s important to know what your hardness and pH is. I believe this can be found on your water supplier’s website.

Thank you! Yes I’ve been looking at that one online I still have my old tank and filter. I’m assuming that will be good to use?

 

[SJX]

The gravel was just over a year old. Yes we do have quite hard water I think. I’m with southern water, do I give up with the fin rot treatment for now? How much water change should I do today. I have 110l tank.

Unfortunately many shops say things are fine when they are not fine. For example, anything above zero for ammonia and nitrite is not fine. When getting the water tested at a shop always make them write down the numbers.



This could be the problem. While the gravel will contain bacteria if the old tank had been running for years, if it had not been running long nearly all the bacteria would have been in the old filter. Using a new filter meant losing a lot of the bacteria so the tank is now trying to grow a lot more. Having your own test kit, preferably a liquid one, means you can test as soon as the fish start behaving oddly and see if there's a problem.
I suggest you get the tank water tested as soon as you can and get the numbers this time. The important ones are ammonia and nitrite - and as strips don't include ammonia, if the shop uses a strip make sure they also do an ammonia test. Once you have the results you'll know if ammonia and/or nitrite is the problem and if it is the "cure" is daily water changes until they remain at zero. In fact I would do a large water change without waiting for the results, just in case. A water change won't harm things but it could help. But take a sample of water for testing before changing the water.

foxgirl makes a good point about hardness. In West Sussex I would expect your water to be hard, but your water company's website should confirm this. If you can't find hardness on the website, tell us the name of the water company and we'll see if we can find it

 

[foxgirl158]

Thank you! Yes I’ve been looking at that one online I still have my old tank and filter. I’m assuming that will be good to use?

How big is it?
How long has it been empty?
You might have to let it cycle depending on how long it’s been empty. @Essjay could probably tell you more than I can on that front.

 

[SJX]

How big is it?
How long has it been empty?
You might have to let it cycle depending on how long it’s been empty. @Essjay could probably tell you more than I can on that front.

It’s 54l and just over 2 weeks now

 

[foxgirl158]

It’s 54l and just over 2 weeks now

54l is plenty for a betta you might have to add tannins or organic material to lower your water hardness and pH, depending on what the exact parameters you find are.

 

[foxgirl158]

54l is plenty for a betta you might have to add tannins or organic material to lower your water hardness and pH, depending on what the exact parameters you find are.

I would get that set up and going right away. Even if you have to wait for it to cycle, the sooner you get it going the sooner you can move the betta.

 

[SJX]

I would get that set up and going right away. Even if you have to wait for it to cycle, the sooner you get it going the sooner you can move the betta.

Will do that now

 

[Essjay]

There should have been a lot of bacteria in the gravel so it shouldn't take long to make up the numbers of bacteria.

If the media in the old filter are even slightly damp, most of the bacteria will still be alive. It's when media is totally and utterly dry that the bacteria will have died.
I agree, if you can set the old tank back up, one betta in that volume won't make a huge amount of ammonia, so even if the media are completely dry it should be OK to move the betta into it - as long as you have a test kit of your own to test ammonia and nitrite every day.





With hard water, long term the soft water fish won't do well. They are likely to get calcium deposits in their organs, especially their kidneys, which means they'll lead shorter lives than they would in soft water. Going forwards, if you get more fish I would stay with hard water species. They include many rainbowfish as well as livebearers ranging from small species to those which need huge tanks.

 

[Colin_T]

Post pictures of the fish.

If a fish ever dies or looks unwell, do a 75% water change and gravel clean the substrate every day for a week, or until the problem is identified.
Make sure any new water is free of chlorine/ chloramine before it's added to the tank.

By using a new filter, you probably have an ammonia and or nitrite reading in the water. This is caused by fish food and waste breaking down and no beneficial filter bacteria to convert it into nitrate. Water changes will help to dilute any nutrients like ammonia and nitrite, and will also dilute any disease organisms that might be in the water.

If the old filter is still working and wet, move some of the fish back into the old tank, or move the old filter into the new tank so it can help clean up the water.