If a soft water fish is raised in hard water, would it be okay to not use RO water?

[FishFriend0]

I was thinking…
Surely the fish at my LFS have been bred in hard water so do I need to use RO water?

 

[Magnum Man]

without knowing your local fish store, most fish stores can't breed fish fast enough to not be sold out all the time, so "most" get fish shipped in to sell, at minimum to supplement what they also breed...

personally at home, I have hard alkaline water, & had really bad luck with most soft water fish... I was able to keep a few Asian fish and a few plecos, but most all my soft water fish were dying, until I put in a dedicated RO unit for the aquariums...
I had pretty good luck with rainbow fish, & others that tolerate hard water, even if they didn't naturally like the alkaline...

 

[Uberhoust]

You can often keep fish outside their normal water hardness requirements but my experience is that they don't do well, and some will outright die. Agree with @Magnum Man, the fish are typically not in the store long enough to matter what the store's hardness is. If you keep to fish that match the water you have you will have fewer issues. Mixing water, RO, all can be a pain to maintain.

 

[sharkweek178]

And the thing is; whether you have soft or hard water, there are lots of great options either way. It's really best to work with what you have instead of trying to chase a parameter.

 

[GaryE]

There's a huge difference between what fish will live in, and what eggs will develop in. Chances are, if the fish are from rainforest, softwater habitats, they had to have been bred is softwater Asian fishfarms, then shipped to your store.
It's been my experience that you can breed some softwater species in medium water, but you get far fewer fry. Farms want as many as they can crank out, and they tend to be situated in softwater zones. That's because of the popularity of South American fish.
A lot of hobbyists keep their fish out of the water they are adapted to, and they live. I used to think I was going great if my cardinals lived to five in my then 140ppm water, but when I moved to 80ppm tapwater, suddenly 7 to 9 and beyond started happening. That's one person's story, but there is credible hobby reporting that softwater fish can have shorter lifespans in harder water.
Then again, I have also read cardinals are seen as annual, one year lifespan fish in the wild. So the lifespan versus quality of life kicks in, and I have no answers there.

 

[seangee]

I kept soft water fish in hard water for years following that logic. The average life of my fish (including cardinals) was 12-18 months. Now I use RO the average life for the same fish is 6-7 years. My fish are also much brighter coloured now.

 

[sharkweek178]

A few generations of breeding is not going to overcome thousands of years of evolution.

 

[AdoraBelle Dearheart]

From what I've read here (maybe @Byron or @Essjay ) have links to the studies, the problem is that soft water fish have evolved to retain mineral content when they find it, since it's harder to come by the essential minerals when in very soft water, but they still need trace amounts. While hardwater species like mollies are the opposite.

So the damage to soft water fish that are living long term in hard water is cumulative. The retained minerals end up causing blockages, especially to the kidneys, leading to a short lifespan.

I can't go looking for research to back that up right now, but hoping others here might be able to lay their hands on it, I'm sure I've seen papers about it shared here before.

 

[FishFriend0]

My water is 280ppm or something crazy like that so I’ll just stick to live bearers and maybe some rainbow fish and maybe in the future I’ll fork out far an RO filter, thanks for the help guys!

 

[AdoraBelle Dearheart]

My water is 280ppm or something crazy like that so I’ll just stick to live bearers and maybe some rainbow fish and maybe in the future I’ll fork out far an RO filter, thanks for the help guys!

You could always collect rainwater, if you have a garden, aren't in too polluted an area, and can set up a waterbutt.

My water is 253ppm, so when I wanted otocinclus and pygmy cories, and couldn't afford/easily do RO, I starting using a 50/50 mix of rainwater (basically like RO) and my tap water in my 15.5g tank. Meant a smaller tank, but the pygmies breed like mad, so it seems to work for us! And can then still scratch that softwater itch.

Or most fish stores sell RO water, which is cheaper than installing your own device.

 

[seangee]

I don't recall the name right now but its much cheaper if you use the stations that window cleaners use for their RO

 

[AdoraBelle Dearheart]

I don't recall the name right now but its much cheaper if you use the stations that window cleaners use for their RO

I was blanking on the name too, and I think it was you who told me about those RO stations

 

[Magnum Man]

Is it deionized water

 

[Lcc86]

I don't recall the name right now but its much cheaper if you use the stations that window cleaners use for their RO

Spotless Water is one company (my partner is a window cleaner lol). I don't use it myself but you may find one near you.

 

[Essjay]

From what I've read here (maybe @Byron or @Essjay ) have links to the studies

It's Byron who knows about the studies. From what I remember it was discovered that cardinal tetras kept in hard water developed deposits in their kidneys.