Water hardness/softness

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Jan 6, 2019
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Hello everyone,

So seeing as I’ve been told that my water is soft at 38ppm, I’ve been scouring the internet looking for fish I may want down the road. Problem is, so many of the fish I find myself looking at want 45-60ppm or above (at least according to seriously fish). I don’t want to make any fish suffer by sticking them in something way softer or harder than what it can handle. My question is: if my water is at 38ppm, can I still look into fish that are ~45ppm and a bit above? I’m not aiming to stick any 200ppm+ fish into the aquarium, I just wish to know that if the minimum hardness is 15-20ppm above mine, that the fish wouldn’t suffer and die horrible deaths or anything.

Thanks so much!
To add to what has been said, as long as you acclimate them properly, and they aren't to far out of the range then they should be fine.
Just make sure to drip acclimate.
This helps fish not get a large shock when entering a different water body than they are currently in.
Some things to keep in mind with these ranges. In some cases, a species may be very specific in its requirement concerning GH. Most species that are soft water fish will not have problems going below the range, but they will have accelerating problems the higher the GH. For more than 30 years I have kept dozens of soft water species in a GH of less than 1 dH, or 0-7ppm. Many of these would be fine with higher GH, up to a point, depending upon the species. With a GH of 38ppm, you basically have the entire fish fauna of most of South America, plus much of SE Asia.

If you have specific species/ranges to question, post and I'll take a look.

BTW, I gave up drip acclimating years ago when a biologist correctly advised me that fish are not going to adapt over a period of one or two or even six hours, but over a period of weeks, if they can even adapt at all (depends upon the numbers). Float the bag to equalize temperature, then release the fish but not the bag water into the aquarium. Some use a small net, other pour the bag of water/fish into a bucket to more easily net out the fish.
Ditto, do drip acclimation and they will be fine (a good practice anyway, because you never know what type of water they were being kept in). The difference between 38 and 50 is not that much, both are considered quite soft.

What you may have trouble with are snails and shrimp. They need carbonates and calcium to create their shells, with levels that low that could be a problem. I also have very soft water and have difficulty keeping snails alive for that reason. What I’ve done before to help my snail population is add some baking soda and calcium chloride to my water changes. Calcium chloride is usually sold as GH up for spas. Baking soda is sodium bicarbonate, carbonates in it thereby increasing KH; and calcium is one of the two components of GH (the other being magnesium which can be increased by adding Epsom salts). However…I don’t really recommend this practice to everyone unless you can be very slow with the increase, and very consistent with matching KH and GH with your water changes. Not using straight tap water for water changes does add a whole other thing to worry about and potentially get wrong, you have weekly testing to do then and possibly additional water changes to do if you mess up. But, it can be done.

If for some reason down the road you need to take this route, or anyone else who may be reading, here‘s a link to a calculator:

In this you can input the gallons of your tank and what you are adding and it will tell you how much to add to get x ppm of whatever it is.

Make sure it‘s Actual gallons of water, not nominal tank size which would be considerably higher. It’s best to use a calculator for figuring this out…you have to take into account how high your water line normally is on the tank, and how much substrate or hardscape you have.

Here‘s a calculator for this purpose:

For instance my tank is nominally called a 65 gallon tank. However when I do the calculation, it’s only holding 48 gallons of water. Pretty big difference!
I never drip acclimate, even when receiving fish from the wild. It simply leaves the fish exposed to ammonia/ammonium for longer, and doesn't last long enough if an adjustment is needed. With water as soft as yours, you're in an ideal situation for the fish @Byron mentioned, as well as my favourites - Western African species.

You can see if 2 aquarists are in the same room, you have 7 opinions... sort through, read the reasons for what we say and decide. I have a background where I've unpacked many dozens of wild shipments of very delicate fish. If we killed them with our techniques, we'd be broke, as well as irresponsible. Once temps are equal, just pour them off into a bucket and net them out into the tank.
I understand perfectly and value the ideas proposed.
If I may say my idea of drip acclimation is not to acclimate the fish but to lessen the shock of entering a new area.
I understand that a fish cannot "acclimate" in 30min-1h of drip but it eases the fish in to the current conditions of the tank.
This is what I meant.
Just to not shock the fish.
Angelfish, discus, most tetras, most barbs, Bettas, gouramis, rasbora, Corydoras and small species of suckermouth catfish all occur in soft water (GH below 150ppm) and a pH below 7.0.

Livebearers (guppies, platies, swordtails, mollies), rainbowfish and goldfish occur in medium hard water with a GH around 200-250ppm and a pH above 7.0.

If you have very hard water (GH above 300ppm) then look at African Rift Lake cichlids, or use distilled or reverse osmosis water to reduce the GH and keep fishes from softer water.

If you want to increase the hardness of the water, add a Rift lake water conditioner. It will contain calcium and magnesium, and a few other things that will increase the pH, GH & KH.
Oh my gosh, thanks so much for all the helpful information everyone! If I stumble onto certain fish that stand out to me I’ll definitely run it by you Byron! Right now I’ve been really into Japanese rice fish and shiners (rainbow shiners and other varieties) but with my kuhli loaches the temp seems to be incompatible with shiners. I’d love to know any fish that look even a little similar if shiners won’t work at all, as I find their color stunning. Any help with clarification as to those two fish types would be awesome. Thanks again everyone for all the info! I’m so appreciative of all the help :):)
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I know next to nothing about Japanese Rice Fish or Shiners, other than the former are native to SE Asia and prefer cooler tropical temperatures (low 70'sF) and the latter are native to the USA and are temperate. Neither would work in a heated aquarium with tropicals. But there are similar-looking fish among the Asian cyprinids, look at the danios and rasboras families.
Got it, there’s definitely some danios and rasboras I’ve found cool looking, and I’ll try to look into cool varieties that would suit my environment

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