# How dangerous is hard water for soft water fish?



## growingthings (Oct 28, 2011)

how odd - i had the same conversation today in a local aquatic centre, reguarding Apistos and Blue Rams. Seems according to the owner that fish are put into catagories such as hard/soft water etc depending on where they originate from in the wild. If a supposed soft water fish has been successfully reared in a hard water enviroment then it would appear they are deemed hard water fish, although they are unlikely to breed in hard water. Im still unsure though. I tend to always buy fish that are bred locally so they come from the same type of water.


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## FriendsNotFood (Sep 21, 2010)

http://www.wetwebmedia.com/FWSubWebIndex/fwhardness.htm

"For some small fish adapted to soft water conditions, the minerals in hard water are thought to cause blockages in some of the organs. Dissection of neon and cardinal tetras has revealed damaged kidneys in specimens kept in hard water aquaria. "

Seems like some soft water fish are only affected by hard water in the long run and simply don't live as long as they would in soft water. Their bodies aren't adapted to the amount of minerals in hard water. And obviously they won't breed. Not sure how much hard water actually shortens their lifespan though.


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## Mxx (Dec 29, 2010)

FriendsNotFood said:


> http://www.wetwebmedia.com/FWSubWebIndex/fwhardness.htm
> 
> "For some small fish adapted to soft water conditions, the minerals in hard water are thought to cause blockages in some of the organs. Dissection of neon and cardinal tetras has revealed damaged kidneys in specimens kept in hard water aquaria. "
> 
> Seems like some soft water fish are only affected by hard water in the long run and simply don't live as long as they would in soft water. Their bodies aren't adapted to the amount of minerals in hard water. And obviously they won't breed. Not sure how much hard water actually shortens their lifespan though.


I did recently lose an Apistogramma agassizii to 'Dropsy' come to think of it. So it could be that mineral build-ups caused the kidney failure resulting in the Apisto retaining water terminally... That could certainly fit the symptoms.


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## Sharkfood (May 2, 2010)

It depends almost entirely on the fish.

You say your water is very hard, but didn't actually post any parameters, so it's hard to make a good guess.

For almost all fish, almost all tapwater is fine. Extreme conditions are considered extreme because they are so far away from the usual, that it's unusual for anything to live in them.

If you have African cichlid water coming out of your tap, then most fish won't tolerate it very well. If you have water like mine,9-10GH, 4KH (varies up and down throughout the year some) and a pH around 7.4, then I can tell you from experience that just about anything from from South America will do just fine, including Discus and Apistogrammas. If you're running a mineral content you can measure with a cheapo, reef tank specific gravity meter, then expect them to be pickled.


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## longbeach (Nov 2, 2011)

Many of the fish will mostly adapt to a wide range of parameters but successful breeding may never happen...it's all part of their evolution in that apistos(example) being from soft acid water, their eggs shells are thick and won't adapt to hard water.


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## Mxx (Dec 29, 2010)

I've measured my tank's hardness parameters now - 
GH = 180 ppm (or 10 degrees DH)
KH = 130 ppm (or 7.3 degrees DH)

This was 2 days after a 50% weekly water change, with at least 1 cup of sphagnum peat moss having been added to the filter then.

My tap water is as follows:
GH = 240 ppm (or 13 degrees DH)
KH = 150 ppm (or 8.4 degrees DH)

So the peat seems to be having some effect in terms of softening the water, but not by an enormous amount. I do worry however that I'm causing major fluctuations in water conditions if every water change is going to cause the hardness to suddenly spike by several dozen ppm each time. 

These parameters would be great for keeping African Cichlids, but Apistos and Cardinal Tetras perhaps not quite so much... I'm not worrying about trying to breed any, or successfully breed any for the moment in any case, but I don't want them to be unhappy!

And is water this hard going to cause me problems in trying to keep some plants? There are some I've not had success with, but I'd thought that was more likely due to underfertilization.


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## mgamer20o0 (Mar 8, 2007)

> It depends almost entirely on the fish.


i think this is the answer. it really depends on the fish. some wont get egg development when breeding in the harder water. some just dont adapt as well. 

one thing ill also note is farmed fish vs wild fish. farmed fish more likely to come from water not typical of their natural environment and often does better then wild fish. 

so again it just depends on the fish.


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## Robert H (Apr 3, 2003)

It always depends on the fish specie. Some species are more sensitive than others. There are many professional breeders that keep to the known specie parameters while others purposely acclimate generations to go outside those parameters. The important thing would be to find out what the water parameters are of where you bought the fish, and if possible the parameters of the supplier to where you bought the fish.

Providing soft or acidic water is not that difficult, just rather time consuming. If you are not willing to do that, I would stick to fish species that are known to flourish in the parameters you have.

People face the same challenges with plants. While many plants can tolerate a wide range of parameters, there are many that are considered more difficult because they thrive in soft water and others that thrive in very hard water, (far fewer)


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## Mxx (Dec 29, 2010)

Anyone know then what the typical water parameters would be for the Czech Republic? (Which is where many of the farmed fish here such as my A. borelli come from, and I somehow suspect my LFS doesn't quite know. Although I might have preferred wild caught specimins, which seem to have a lot more colour and iridescent colour than the farmed ones i've obtained had, unless they're to colour up further still as they reach full maturity.)

I thought that peat filtering would get achieve soft water for me. Either that alone is not sufficient, or I should take out all my filter floss and replace it with much more peat than I'm using currently, at least until I can invest in an RO unit. But that doesn't resolve the problem I'd be having with bouncing hardness due to water changes, unless I was to filter my water change water through peat as well, until it tests to where it matches the tank's hardness, and then warm it to match the temperature as well... So perhaps stable hard water parameters are nevertheless preferable to fluctuating conditions.


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## RukoTheWonderDog (Nov 11, 2011)

My water out of the tap has a pH of 8.2 and is very hard due to large deposits of limestone in the water table. I kept many soft water species like cardinals and had okay results with most fish. Rams did not do well and I eventually lost 3 of 4. It was apparent that the fish did not thrive in the water conditions. Growth seemed slower and the colors were definitely washed out. I tried peat moss and lemon juice but was still stuck with the high GH & KH. A RO system was the only choice for me.

Your line bred & farmed fish are more likely to be tolerant to foreign water parameters than wild caught fish.

Now that I use reconstituted RO water for all my tanks, I'll never consider another option as the results have been fantastic.


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## Wasserpest (Jun 12, 2003)

Mxx said:


> Anyone know then what the typical water parameters would be for the Czech Republic? (Which is where many of the farmed fish here such as my A. borelli come from, and I somehow suspect my LFS doesn't quite know. Although I might have preferred wild caught specimins, which seem to have a lot more colour and iridescent colour than the farmed ones i've obtained had, unless they're to colour up further still as they reach full maturity.)


It's a big place. Some regions like Plzen/Pilsen are famous for their extremely soft water, while the karst landscapes in the eastern parts north of Brno result in very hard water. So nothing typical really.



Mxx said:


> I thought that peat filtering would get achieve soft water for me. Either that alone is not sufficient, or I should take out all my filter floss and replace it with much more peat than I'm using currently, at least until I can invest in an RO unit. But that doesn't resolve the problem I'd be having with bouncing hardness due to water changes, unless I was to filter my water change water through peat as well, until it tests to where it matches the tank's hardness, and then warm it to match the temperature as well... So perhaps stable hard water parameters are nevertheless preferable to fluctuating conditions.


Rather than messing around with peat, you could buy gallons of RO water and use that during water changes, perhaps mixed with tap water in a fixed proportion. That way you will get more stable parameters which indeed are preferable.


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## Doc7 (Apr 7, 2011)

I've had cardinal tetras live for a year and have beautiful coloration in hard water with a PH of 8.3, and corydoras were breeding (eggs were eaten so don't know final results) - I don't know the eventual life time of the cardinals but they're not sick or unhealthy looking in the relatively short 1-year term.


I hope to keep an Apistogramma and will just have to see how it ends up in terms of dealing with my water chemistry.

If I ever want to keep a softwater species that NEEDS different conditions to thrive, it will have to be a nano tank that I can change water by lugging a few bottles worth from the large RO-DI system I have at work. Living in an apartment I don't see myself installing an RO-DI set up anytime soon.... add it to the list of plumbing etc that i want to do for a tank once I get a house : )


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## trixella (Jan 24, 2011)

Doc7 said:


> I've had cardinal tetras live for a year and have beautiful coloration in hard water with a PH of 8.3, and corydoras were breeding (eggs were eaten so don't know final results) - I don't know the eventual life time of the cardinals but they're not sick or unhealthy looking in the relatively short 1-year term.
> 
> 
> I hope to keep an Apistogramma and will just have to see how it ends up in terms of dealing with my water chemistry.
> ...


Cardinals can live 5 or more years when given soft water (2-5 degrees hardness) conditions. The minerals in the hard water builds up in their kidneys/organs and causes them a much shorter lifespan.

You should be able to buy RO water from either your lfs or at one of the water machines at most grocery stores. That's what I do for RO since I don't want to buy my own filter. Instead of using straight RO and having to buy mineral supplements for the RO water, I just mix the RO half and half with my hard tap water and that softens it up just the right amount for my cardinals.


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## Raul-7 (Oct 17, 2003)

As everyone mentioned it depends entirely on the species and to a lesser extent whether or not they were tank-bred or wild caught. 

IME, wild-caught species should always be kept in water that resembles their original habitat. This is true for a lot 'difficult' species like Chocolate gouramis, Parosphromenus sp., wild Angelfish, Cardinals, wild Apistogramma sp., etc. 

An RO unit is the best investment you could have if you wish to keep soft-water species. My Neon's went from surviving 1 month [in 300+ TDS] to surviving for years just by softening the water. I had similar results with the notorious Chocolate gourami, first batch lasted a week. The next time I housed them in pure RO water [TDS ~25ppm] and they went strong for a year before slowly dieing off.


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## Mxx (Dec 29, 2010)

Interesting, consensus call seems to suggest that even in cases where species inappropriate hardness is not immediately dangerous, it will nevertheless be dangerous to my fauna in the mid to long term... 

Sounds as if I should for best results at least get a 5 gallon jug and start hauling in RO water from the LFS, even if it results in cutting back on water changes.


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