Molly died ! Need some advice!

[Chris king]

hi everyone as the title suggests one of my mollys died today suddenly and when I mean suddenly I was watching them all this morning and this afternoon and they all seemed fine all feeding well ect . Then this afternoon all
Of a sudden I noticed he was swimming on its side and then suddenly shooting off against the tank and then he was floating around and occasionally darting forwards . Within 10 mins he was dead ... I immediately tested my water levels and I have

7.4ph
0 ammonia
0 nitrite
20ppm nitrate

Tank cycled fine and I have actually had 5 platies in there for 4 weeks now and there fine always have been .
Stock levels are
5 platies
2 mollys

200l tank

I’ve been taking things slow to not overwhelm my filtration (Fluval 306) and the 2 mollys where added 6 days ago ..
I must say I have had a high nitrate level isssue for a few weeks but iv resolved that with a nitrate filter for my water (high nitrate in my tap water 50ppm) maybe this was the cause ?
I’m baffled by it as it was so fast! No marks on him nothing really to report other than fine 1 min and not the next!

Just worries I have a problem in my tank!
Any advise will be helpful
Thanks
Chris

 

[Byron]

It is difficult to diagnose specific issues many times. This could have been genetic, or stress from the store tank/netting/new environment [this is extreme stress for any fish], or internal injury that occurred when being netted/transported, or the nitrates. Mollies are very sensitive to nitrogen issues (ammonia, nitrite, nitrate), and these leave permanent problems for the fish even if they do live through it.

The pH is basic but a tad on the low side for mollies, so do you know the GH? This is more critical for most fish, and mollies need harder water than what other livebearers might manage in. Mollies in water that is not moderately hard or harder will weaken rapidly.

 

[Chris king]

Thanks for the reply , GH is 60 if that helps all other fish still seem perfectly fine . So strange he deteriorated so fast!

 

[Essjay]

What is the unit for the hardness, and where did you find that number? 60 is too high to be degrees (dH) which leaves mg/l (aka ppm) but mg/l of what? UK water company websites usually use mg/l calcium; other countries, and most test kits use mg/l calcium carbonate.

If the 60 is mg/l calcium carbonate (3.3 dH) it is very soft water, far too soft for mollies and other livebearers. If it is mg/l calcium, that converts to 150 mg/l calcium carbonate (8.4 dH) which is still too low for livebearers.


If you can confirm what the unit for that hardness of 60 is we will be able to say whether or not the water is too soft for livebearers to live in.

 

[Chris king]

It reads as ppm (mg/l)

 

[Byron]

Following up on essjay's post, you need to confirm this. But whichever, it is much too soft for mollies so that is most probably the cause of the molly's decease. Mollies do not last long in soft water.

At this stage, subject to confirmation of the GH (but only relevant if it turns out to be much harder than either possibility essjay mentioned), you should return the second molly and the platies. A GH below 10 dGH (= 179 ppm) is not sufficient for livebearers long-term. Platy will manage longer than will mollies, but the end is inevitable as they are weakened by this lack of mineral and that causes stress which leads to further issues and weakness.

There are lots of suitable soft water species. Almost all fish from South America and SE Asia are in this group. And there are many small and medium sized species.

 

[Chris king]

60 mg/l
Ok, is there any way to raise my gh level??
I like my fish

 

[Byron]

60 mg/l
Ok, is there any way to raise my gh level??
I like my fish

The unit mg/l (milligrams per liter) is identical to ppm (parts per million) just so you know. So 60 mg/l = 60 ppm which is the same as 3 dGH. This is very soft water.

It is much easier to have fish suited to your source water than adjusting the water for fish. But it is possible to adjust parameters, and this is easier making soft water hard than the reverse. I have gone through this in the past.

The easiest way is to use a calcareous substrate. This will slowly release calcium and magnesium, raising the GH. Provided you stay with livebearers and have no soft water fish species at all, it doesn't matter how high the GH/pH get with the substrate, and it will be stable going forward.

You can also use a mineral additive to increase GH. Seachem make one, and another is the rift lake mineral salts. These can get expensive as they have to be used continuously, and at water changes you will have to prepare the fresh water outside the aquarium. This is more effort, and should you need an emergency water change can be a lot of work.

There are so many aquarists cursed with hard water who want to keep soft water species--you should consider yourself lucky to have soft water. But you need fish suited to it. The livebearers are all in difficulty right now, and this is not always reversible.

 

[Chris king]

Ok I’ve just seen seachems one replenish . Il go to me lfs in the morning and try and get someone to raise it up as I like what I have for now . It’s a shame I must say I did a lot of research before getting into this world and gh levels never came up much it was all ammonia nitrite nitrate over and over
anyway thanks for your help appreciate it!

 

[Colin_T]

... they all seemed fine all feeding well ect . Then this afternoon all of a sudden I noticed he was swimming on its side and then suddenly shooting off against the tank and then he was floating around and occasionally darting forwards . Within 10 mins he was dead ... I immediately tested my water levels and I have

This is usually caused by chemicals in the water, a stroke, or a bacterial or protozoan infection in the brain.

Mollies have lots of issues in soft water and are usually infected with protozoans when you buy them. The protozoans do better in softwater so the combination of your very soft water (60ppm is very soft) and the new mollies would suggest protozoan infection in the brain.

Increasing the general hardness to 250ppm and adding salt should prevent any further deaths from this.

You can add rock salt (often sold as aquarium salt), sea salt or swimming pool salt to the aquarium at the dose rate of 1 heaped tablespoon per 20 litres of water. If there is no improvement after 48 hours you can double that dose rate so there is 2 heaped tablespoons of salt per 20 litres.

If you only have livebearers (guppies, platies, swordtails, mollies), goldfish or rainbowfish in the tank you can double that dose rate, so you would add 2 heaped tablespoons per 20 litres and if there is no improvement after 48 hours, then increase it so there is a total of 4 heaped tablespoons of salt per 20 litres.

Keep the salt level like this for at least 2 weeks but no longer than 4 weeks otherwise kidney damage can occur. Kidney damage is more likely to occur in fish from soft water (tetras, Corydoras, angelfish, gouramis, loaches) that are exposed to high levels of salt for an extended period of time, and is not an issue with livebearers, rainbowfish or other salt tolerant species.

The salt will not affect the beneficial filter bacteria but the higher dose rate will affect some plants. The lower dose rate will not affect plants.

After you use salt and the fish have recovered, you do a 10% water change each day for a week. Then do a 20% water change each day for a week. Then you can do bigger water changes after that.

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Don't get the Seachem replenish because it has potassium and sodium chloride in. The sodium chloride isn't that bad for livebearers but potassium can cause kidney damage in fish and all animals.

Get a Rift Lake water conditioner and some limestone, coral rubble or shells to put in the tank. Use the Rift Lake conditioner at half strength and make the water up at least a couple of hours before using it (preferably 24 hours). After a few water changes check the GH, you want it around 250ppm for mollies. Other livebearers will be fine with a GH of 200ppm but the mollies need 250ppm so get it to 250ppm.

Get a big bucket, add water, add Rift Lake conditioner and aerate it for a few hours. Then add dechlorinate to it about 30 minutes before you use it, aerate for 30minutes and then use in tank.

The Rift Lake conditioner will raise the pH as well as the GH and KH, this is fine for the livebearers. However, if you get any ammonia in the water it will be very toxic in water with a high pH so make sure you monitor the water quality and maintain the filter.

 

[seangee]

It is much easier to have fish suited to your source water than adjusting the water for fish. But it is possible to adjust parameters, and this is easier making soft water hard than the reverse. I have gone through this in the past

This is really good advice and you may want to think through your stocking plans. 200l is a good size tank and far more tropical fish prefer soft water. Creating the ideal environment for your live bearers means that your tank becomes unsuitable for many other fish such as tetras, rasboras etc etc.

I am not saying don't do it but be aware of the implications. It is a long term commitment. Personally I have tap water that is perfect for mollies and I do adjust my parameters to accomodate soft water fish in one of my tanks. This can be expensive and time consuming and requires planning ahead. My other tank is much easier because it gets water straight out of the tap (although, like you, I do have to filter out nitrates).