20 Gallon Stocking Ideas

[Byron]

GH is extremely important; there would be far fewer fish dying in this hobby if aquarists understood and matched GH. I'll explain.

GH is the measurement of dissolved calcium and magnesium in water. Water is the most powerful solvent on this planet, which means it easily and readily assimilates what it comes into contact with when this can be assimilated. Each species of freshwater fish has evolved to function in a very specific water environment. In very general terms, hard water fish must have these minerals in the water because their physiology cannot function without them. While soft water fish do not need these minerals. Fish do not drink because they continually take in water via osmosis through every cell; this water, and substances dissolved in it, enters the bloodstream and internal organs. If the water is lacking these minerals, hard water fish cannot otherwise acquire them, that is how they are designed by evolution, and they weaken and slowly die. Death is often from other causes because the fish being so weakened cannot deal with them. In soft water fish this water passes through the kidneys which are designed to remove salts in the water. The result is calcium blockage of the kidneys, and the fish dies.

If the GH is 80 ppm, that is equivalent to 4 dGH, which is soft water, almost very soft. You are fine for soft water species, provided they are suitable for the tank size obviously. Your gourami are good. Your guppies are not. You could re-home them and select other soft water species (best for the guppies).

 

[hannahbatts]

The GH is the general hardness. Hard water fish like mollies and guppies take their nutrients and minerals from the hard water. Soft water lacks the minerals they need so they are starved of this and cannot function well in the long term, leading to a shorter life.

Soft water fish are the opposite, when placed in hard water they are overloaded with minerals they cant absorb and die sooner as well

Thank you for clarifying! That was really helpful.

Do you know any suitable soft water fish that would work in my tank? The tap water in my town is soft, so the only way I'd be able to get harder water is by using pre-packaged aquarium water.

 

[hannahbatts]

GH is extremely important; there would be far fewer fish dying in this hobby if aquarists understood and matched GH. I'll explain.

GH is the measurement of dissolved calcium and magnesium in water. Water is the most powerful solvent on this planet, which means it easily and readily assimilates what it comes into contact with when this can be assimilated. Each species of freshwater fish has evolved to function in a very specific water environment. In very general terms, hard water fish must have these minerals in the water because their physiology cannot function without them. While soft water fish do not need these minerals. Fish do not drink because they continually take in water via osmosis through every cell; this water, and substances dissolved in it, enters the bloodstream and internal organs. If the water is lacking these minerals, hard water fish cannot otherwise acquire them, that is how they are designed by evolution, and they weaken and slowly die. Death is often from other causes because the fish being so weakened cannot deal with them. In soft water fish this water passes through the kidneys which are designed to remove salts in the water. The result is calcium blockage of the kidneys, and the fish dies.

If the GH is 80 ppm, that is equivalent to 4 dGH, which is soft water, almost very soft. You are fine for soft water species, provided they are suitable for the tank size obviously. Your gourami are good. Your guppies are not. You could re-home them and select other soft water species (best for the guppies).

Thank you so much for the thorough explanation

Is there a specific way I can harden the water? My tap water runs soft.

 

[Essjay]

You don't need to make the water harder, just choose fish that like soft water. You did mention getting tetras in your first post, and the majority of tetras prefer soft water.

 

[hannahbatts]

You don't need to make the water harder, just choose fish that like soft water. You did mention getting tetras in your first post, and the majority of tetras prefer soft water.

Ok, I wasn't sure about the tetras that's why I asked

Are all tetras ok in softer water, or do I still need to be careful depending which kind I end up with?

 

[hannahbatts]

Ok, I wasn't sure about the tetras that's why I asked

Are all tetras ok in softer water, or do I still need to be careful depending which kind I end up with?
Edit- just realized you said most. To be specific are neons ok in soft water?

 

[Essjay]

Yes, neons need soft water. There the odd one or two tetras that have higher hardness ranges.

The best place for research is https://www.seriouslyfish.com/knowledge-base/ They give the pH, hardness, temperature and tank size needed by fish as well as information on how to care for them (food, tank decor, suitable tank mates etc)


Edit to add - they do use different units in different fish profiles; if you need to convert tank size (cm/inches) temperature (deg F/deg C) or hardness (dH/ppm) there is a calculator on here in the Useful Links menu.

 

[hannahbatts]

Yes, neons need soft water. There the odd one or two tetras that have higher hardness ranges.

The best place for research is https://www.seriouslyfish.com/knowledge-base/ They give the pH, hardness, temperature and tank size needed by fish as well as information on how to care for them (food, tank decor, suitable tank mates etc)

Perfect, thank you!!! I will check out that website and post updates.

 

[Byron]

I will just add to what essjay posted, and say that your life as an aquarist will be much easier if you select fish suited to your source water. This makes water changes very easy, compared to adjusting parameters which means preparing water for water changes in another container and then adding the adjusted water to the tank. Water changes are the life of an aquarium, and being able to do substantial regular changes is the key to a healthy successful aquarium.

Yoour GH is actually perfect. All soft water fish will be fine, and the GH at 80ppm (4 dGH) means there is enough calcium and magnesium to help the plants without harming the soft water fish species. Fish requiring moderately harder water would need the GH much higher, 10 dGH and above, depending. But that would then be detrimental to the soft water fish that will be much happier and healthier at 4dGH.

 

[hannahbatts]

I will just add to what essjay posted, and say that your life as an aquarist will be much easier if you select fish suited to your source water. This makes water changes very easy, compared to adjusting parameters which means preparing water for water changes in another container and then adding the adjusted water to the tank. Water changes are the life of an aquarium, and being able to do substantial regular changes is the key to a healthy successful aquarium.

Yoour GH is actually perfect. All soft water fish will be fine, and the GH at 80ppm (4 dGH) means there is enough calcium and magnesium to help the plants without harming the soft water fish species. Fish requiring moderately harder water would need the GH much higher, 10 dGH and above, depending. But that would then be detrimental to the soft water fish that will be much happier and healthier at 4dGH.

Ok, thank you! I'll probably end up adding a few more gourami and a school of tetras

 

[JuiceBox52]

I'd like to add..
So many fish keepers would be jealous of your soft water! There are way more fish suited to soft water than hard and people with hard will often soften but reverse osmosis water which is a lot of effort

 

[Byron]

Ok, thank you! I'll probably end up adding a few more gourami and a school of tetras

Gourami can become a problem. You now have 4 Honey Gourami, I would leave it at that. I don't know if these are male/female but this is about all you would want in this sized tank as far as gourami are concerned.

Male gourami are territorial, to varying degrees depending upon the species and the individual fish. But some of the gourami species can get very feisty when other gourami invade "their" space.

 

[hannahbatts]

I'd like to add..
So many fish keepers would be jealous of your soft water! There are way more fish suited to soft water than hard and people with hard will often soften but reverse osmosis water which is a lot of effort

Thank you!!! I do feel kind of limited due to the size of my tank, but I can't really go much bigger with the space I'm living in unfortunately.

 

[hannahbatts]

Gourami can become a problem. You now have 4 Honey Gourami, I would leave it at that. I don't know if these are male/female but this is about all you would want in this sized tank as far as gourami are concerned.

Male gourami are territorial, to varying degrees depending upon the species and the individual fish. But some of the gourami species can get very feisty when other gourami invade "their" space.

Thank you for the heads up! Unfortunately, I lost a honey and a guppy this morning. I consulted with an employee at my LFS once my honey got sick, who thought it was swim bladder at first, but then told me to treat the tank for a disease once the guppy got sick too. I treated the tank for a bacterial/parasite infection two days ago, and the rest of the fish seem to be doing well. Hopefully they were two unrelated deaths. I will probably pick up another honey and maybe 2 more guppies, along with a school of tetra

**I'm going to give it about a week to make sure the tank is ok before I add more fish.

 

[Byron]

Thank you for the heads up! Unfortunately, I lost a honey and a guppy this morning. I consulted with an employee at my LFS once my honey got sick, who thought it was swim bladder at first, but then told me to treat the tank for a disease once the guppy got sick too. I treated the tank for a bacterial/parasite infection two days ago, and the rest of the fish seem to be doing well. Hopefully they were two unrelated deaths. I will probably pick up another honey and maybe 2 more guppies, along with a school of tetra

**I'm going to give it about a week to make sure the tank is ok before I add more fish.

I would not suggest another gourami unless you know the gender of the ones you have now. If one of these is a male, and assuming the three/four get/got along OK, you should not add any more.