Do rainbowfish go with non-planted blackwater tank?

Rick bose
Member
Well, the title says it all. Can rainbowfish be kept in non-planted blackwater tank? There will be many bogwood and driftwood in the tank. The height of the tank is 12 inch. But since no substrate will be kept in the tank the fish will get 11 inch vertical swimming space. I will keep the water just 1 inch below the top level. There will be lid in the tank.
 
Myyyman
Member
Should be fine, it's more an issue of the affect the blackwater will have on the pH, but it should be fine. I believe they enjoy plants but it's not a must have. What type of rainbows?
 
MacZ
Member
Are we talking actual blackwater or just coloured water? And what species of rainbow?
If it is true blackwater I have to urge you to do at least a thin layer of sand, topped with a leaf litter bed, otherwise the tank may become unstable.

Myyyman said:
it's more an issue of the affect the blackwater will have on the pH
What are you talking about? True blackwater is defined by low pH (among other factors). Faux blackwater is not. In any case, it can't affect its own pH.
 
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Rick bose
Member
MacZ said:
Are we talking actual blackwater or just coloured water? And what species of rainbow?
If it is true blackwater I have to urge you to do at least a thin layer of sand, topped with a leaf litter bed, otherwise the tank may become unstable.



What are you talking about? True blackwater is defined by low pH (among other factors). Faux blackwater is not. In any case, it can't affect its own pH.
I want to keep western rainbowfish and red rainbowfish. I will create the blackwater by almond leaves, coconut leaves, guava leaves or any other leaves that are available here. Also isn't driftwood or bogwood too supposed to release some tannins in the water to make the tank blackwater?

Can you please explain why the tank might become unstable if used leaf bed but not sand?

And if the ph gets too low, I can increase the ph level by putting some rocks that increase ph or by putting crushed shells in the tank. I will monitor the ph level every week.
 
GlennO
Member
Every rainbowfish book or reference that I've read highlights the importance of plants to encourage natural behaviours and good colouration. Having little or no substrate doesn't preclude having plants, they can be kept in containers or attached to driftwood. You could at least hang a spawning mop in there to allow them to do something naturally. My rainbowfish (including Westerns) spawn on a daily basis.
 
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Rick bose
Member
GlennO said:
Every rainbowfish book or reference that I've read highlights the importance of plants to encourage natural behaviours and good colouration. Having little or no substrate doesn't preclude having plants, they can be kept in containers or attached to driftwood. You could at least hang a spawning mop in there to allow them to do something naturally. My rainbowfish (including Westerns) spawn on a daily basis.
I know there are several plants that can grow attached to driftwood. Almost every plants can be grown in containers. There are floating plants too. 2 of my other tanks are heavily planted and I have such plants there too that is grown floating or in containers or in driftwood. Also almost none of them blackwater tanks that I have seen on the internet are well planted. Yes, many are planted somewhat but the plants are few, they can't be called a planted tank. I prefer the looks of blackwater tank without any plants.

2nd reason is the tank will have low lights, even lower lights than that is required for low light plants. And I really can't afford spending more money buying planted lights. So plants in the tank is a big no. If rainbowfish can't be kept in a non-planted tank, then I won't simply kept them but I won't have plants in the tank. Also I don't want to spawn the rainbow fishes and won't put spawning mop too in the tank as I don't like the look of them in a blackwater tank.

I have neon dward rainbowfish in one of my tanks. So won't have any more species on rainbowfish if they can't be kept in a non-planted tank. The tank will have many driftwood and bogwood though if the fishes like hiding or shelter spots.

I don't want to have plants in the tank for 2 reasons. First, I really like the look of the blackwater tank without any plants.
 
GlennO
Member
No problem. Aquatic plants (often very dense on the lake or stream margins) are an integral part of their environment (diet, shelter, breeding etc). You could probably find more appropriate species for the type of setup that you describe.
 
MacZ
Member
Rick bose said:
I want to keep western rainbowfish and red rainbowfish. I will create the blackwater by almond leaves, coconut leaves, guava leaves or any other leaves that are available here. Also isn't driftwood or bogwood too supposed to release some tannins in the water to make the tank blackwater?

Can you please explain why the tank might become unstable if used leaf bed but not sand?

And if the ph gets too low, I can increase the ph level by putting some rocks that increase ph or by putting crushed shells in the tank. I will monitor the ph level every week.
pH and KH are connected. KH (in the hobby this is always meant the sense of acid capacity) determines how much acid (or rather H+ ions) is needed to change the pH.

Just with leaves and wood you won't lower the pH significantly, unless your water has a KH below 1. If the KH is above that the pH will start to fluctuate after every waterchange and in case the botanicals stop leaching humic acids. (Tannins are more the coulouring agents and influence the pH even less.)

Problem is, while just adding acids (e.g. as pH-down) would temporarily lower the pH, the KH is only bound for the time being. Meaning if your KH is too high, the pH will rise again when the acid as a complex molecule is broken down or depleted from the rotting plant matter.

A good layer of sand and mulm has a lot of beneficial microorganisms not only keeping the cycle going but also breaking down leaves and wood and releasing humic and fulvic acids. That way a good layer of plantbased mulm can stabilise the pH in a lower range.
As long as your water has KH, a stabilisation only a bit below 7.0 pH is the likeliest outcome. That will be faux blackwater then.

Real blackwater though has zero KH and GH, a very low conductivity and the pH starts between 6.5 and 6.0 and goes as far down as 4.5.

Edit: And going back to your rainbows: Both species are not blackwater fish. Real blackwater may actually kill them. Faux blackwater is kind of not fitting. But it's almost only the looks, so...
 
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Rick bose
Member
MacZ said:
pH and KH are connected. KH (in the hobby this is always meant the sense of acid capacity) determines how much acid (or rather H+ ions) is needed to change the pH.

Just with leaves and wood you won't lower the pH significantly, unless your water has a KH below 1. If the KH is above that the pH will start to fluctuate after every waterchange and in case the botanicals stop leaching humic acids. (Tannins are more the coulouring agents and influence the pH even less.)

Problem is, while just adding acids (e.g. as pH-down) would temporarily lower the pH, the KH is only bound for the time being. Meaning if your KH is too high, the pH will rise again when the acid as a complex molecule is broken down or depleted from the rotting plant matter.

A good layer of sand and mulm has a lot of beneficial microorganisms not only keeping the cycle going but also breaking down leaves and wood and releasing humic and fulvic acids. That way a good layer of plantbased mulm can stabilise the pH in a lower range.
As long as your water has KH, a stabilisation only a bit below 7.0 pH is the likeliest outcome. That will be faux blackwater then.

Real blackwater though has zero KH and GH, a very low conductivity and the pH starts between 6.5 and 6.0 and goes as far down as 4.5.

Edit: And going back to your rainbows: Both species are not blackwater fish. Real blackwater may actually kill them. Faux blackwater is kind of not fitting. But it's almost only the looks, so...
Will guppies, bronze corydoras and glolight zebra danios go in blackwater tank that I am planning to make?
And yes, I would add a 1.5 inch layer of sand there and maybe add some aponogetons there as they can be kept in extreme low lights. Can you also explain what you meant by "But it's almost only the looks, so.."? English is not my mother tongue, so I sometimes find trouble in understanding such sentences. Also you wrote that those species of rainbowfish shouldn't be kept in faux blackwater tanks too, right?

I really don't know about the kh level of my water or tank waters. I don't have any test kits to know my kh. I don't even know much about kh and several things went above my head about what you said about kh. Anyway, if my just keep leaves and wood and hope that my tank will look blackwater, can't that be done without having knowledge about kh or testing kh? Can guppies, bronze corydoras and glolight zebra danios can be kept in such a tank with leaves and wood waiting for the tank water to turn black without even thinking about kh? Or do I need to care about kh as you said during water changes or if they start releasing humic acids, then ph will fluctuate? Can that happen even if there's sand in the tank and lots of extra bio media like ceramic rings? If ph fluctuates a bit, will it have any effect on these fishes?Can this be done by just adding the leaves and wood and waiting for the colour to show? Or do I really need to gain knowledge and test my kh to keep a blackwater tank? Thanks in advance.
Your reply was insightful and much appreciated. So was GlennO's.
 
Myyyman
Member
MacZ said:
Are we talking actual blackwater or just coloured water? And what species of rainbow?
If it is true blackwater I have to urge you to do at least a thin layer of sand, topped with a leaf litter bed, otherwise the tank may become unstable.



What are you talking about? True blackwater is defined by low pH (among other factors). Faux blackwater is not. In any case, it can't affect its own pH.
Sorry, by this I meant the tannins used to create black water will lower the pH, not the blackwater itself.
 
MacZ
Member
Myyyman said:
Sorry, by this I meant the tannins used to create black water will lower the pH, not the blackwater itself.
I see, but no, they don't really. It's a whole array of organic acids like humic, fulvic, gallic, and yes, tannic acids. But it's not the tannins themselves that do much.
 
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Rick bose
Member
MacZ said:
I see, but no, they don't really. It's a whole array of organic acids like humic, fulvic, gallic, and yes, tannic acids. But it's not the tannins themselves that do much.
Can you please give me a reply if you can and guide me through the basics of blackwater tank and answer my query by telling whether that's possible what's I am thinking?
 
MacZ
Member
Rick bose said:
Will guppies, bronze corydoras and glolight zebra danios go in blackwater tank that I am planning to make?
And yes, I would add a 1.5 inch layer of sand there and maybe add some aponogetons there as they can be kept in extreme low lights. Can you also explain what you meant by "But it's almost only the looks, so.."? English is not my mother tongue, so I sometimes find trouble in understanding such sentences. Also you wrote that those species of rainbowfish shouldn't be kept in faux blackwater tanks too, right?

I really don't know about the kh level of my water or tank waters. I don't have any test kits to know my kh. I don't even know much about kh and several things went above my head about what you said about kh. Anyway, if my just keep leaves and wood and hope that my tank will look blackwater, can't that be done without having knowledge about kh or testing kh? Can guppies, bronze corydoras and glolight zebra danios can be kept in such a tank with leaves and wood waiting for the tank water to turn black without even thinking about kh? Or do I need to care about kh as you said during water changes or if they start releasing humic acids, then ph will fluctuate? Can that happen even if there's sand in the tank and lots of extra bio media like ceramic rings? If ph fluctuates a bit, will it have any effect on these fishes?Can this be done by just adding the leaves and wood and waiting for the colour to show? Or do I really need to gain knowledge and test my kh to keep a blackwater tank? Thanks in advance.
Your reply was insightful and much appreciated. So was GlennO's.
I simply didn't see your last post displayed. I'm here on my leasure time.
The sand layer is great.
"But it's almost only the looks, so.." means: If it's only the visuals of blackwater the waterchemistry is secondary. Of all fish you named only the Cories would work in real blackwater. In a tank that only LOOKS blackwater (faux blackwater) the parameters should be average, pH being at best slightly acidic (between 6.5 and 7.0) so technically you can also keep the danios. For Guppies this is still too low, I wouldn't keep them in a tank like this. No idea if Aponogeton would work, though. Never kept them.

KH in the aquarist's sense means acid binding capacity. Meaning: How much acid has to be added to see a change in pH. The higher the KH the more/stronger acids are needed to lower pH. With leaves and wood and a measurable KH the pH won't go down much. Why you should know your KH: Just as you said, so when there are humic acids (and they will, no doubt about that) released from the material and KH is low the pH might slowly drop. Not fluctuate, just drop.
Sand and Biomedia don't automatically raise KH or pH. Most are inert, meaning neutral.

Small fluctuations (+/- 0.2) are normal over the course of the day and are not bad. More can be detrimental but doesn't have to be. So this depends on the actual fluctuation. A low pH is good for many fish. Corydoras for example, and depending in the species, live in a range between 4.5 and 7.5 pH.

I would definitely recommend researching the background and at least get info on your KH beforehand so you know what you will have to expect. Either pH stagnates or it drops. If it drops you will want to know how low. And that you can only know when knowing pH. You see the problem?
 
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Rick bose
Member
MacZ said:
I simply didn't see your last post displayed. I'm here on my leasure time.
No issue. This happens.
MacZ said:
The sand layer is great.
"But it's almost only the looks, so.." means: If it's only the visuals of blackwater the waterchemistry is secondary. Of all fish you named only the Cories would work in real blackwater. In a tank that only LOOKS blackwater (faux blackwater) the parameters should be average, pH being at best slightly acidic (between 6.5 and 7.0) so technically you can also keep the danios. For Guppies this is still too low, I wouldn't keep them in a tank like this. No idea if Aponogeton would work, though. Never kept them.

KH in the aquarist's sense means acid binding capacity. Meaning: How much acid has to be added to see a change in pH. The higher the KH the more/stronger acids are needed to lower pH. With leaves and wood and a measurable KH the pH won't go down much. Why you should know your KH: Just as you said, so when there are humic acids (and they will, no doubt about that) released from the material and KH is low the pH might slowly drop. Not fluctuate, just drop.
Sand and Biomedia don't automatically raise KH or pH. Most are inert, meaning neutral.

Small fluctuations (+/- 0.2) are normal over the course of the day and are not bad. More can be detrimental but doesn't have to be. So this depends on the actual fluctuation. A low pH is good for many fish. Corydoras for example, and depending in the species, live in a range between 4.5 and 7.5 pH.

I would definitely recommend researching the background and at least get info on your KH beforehand so you know what you will have to expect. Either pH stagnates or it drops. If it drops you will want to know how low. And that you can only know when knowing pH. You see the problem?
Yes, I would definitely do more research before making the blackwater tank. I will definitely research this background and get info on KH beforehand like you said. Are there any articles or page on fishlore about kh and blackwater tank or on any other site? If you know, please share. Yes, now I am understanding what you are saying. Can you tell me how to test the kh of water? Also I would just simply add 1 or 2 aponogetons to see whether they can grow in such a low-light tank. If they works, great. If not, no worries, they are superb cheap here. 14 aponogetons in 1 USD.

Also I may be wrong but I remember in saw in another thread in fishlore where it was said guppies will do good in faux balckwater. I will definitely conduct more research before making the tank blackwater but was it wrong?
And can't I place some rocks like comgo holey stones in the tank that increases ph and maintain a balanced ph in the tank? I will test the ph level every week, or every 2 weeks if needed to.
 
MacZ
Member
Rick bose said:
Are there any articles or page on fishlore about kh and blackwater tank or on any other site? If you know, please share.
The Blog of Tannin Aquatics called "The Tint" is a fountain of knowledge about it. ( ) Otherwise Wikipedia has some quite interesting info. My other sources are in german language, I doubt they are of much use for you.

Rick bose said:
Can you tell me how to test the kh of water?
Test kits. All international companies offer those (Sera, JBL, Fluval, API... pick yourself)

Rick bose said:
Also I may be wrong but I remember in saw in another thread in fishlore where it was said guppies will do good in faux balckwater. I will definitely conduct more research before making the tank blackwater but was it wrong?
Guppies are by no means softwater fish (They need quite high GH and pH) and I would not even keep them in faux blackwater. You technically can, if the water has high enough pH, but otherwise this is all but a fitting environment for them. But I'm not a Guppy keeper. Or livebearers in general. They are very far from my specialties.

Rick bose said:
And can't I place some rocks like comgo holey stones in the tank that increases ph and maintain a balanced ph in the tank?
Rocks like those usually bring hardness (GH and KH) and pH to quite high levels and stabilize there.
I would either go for hard water or soft water. Taking the look of blackwater with leaves and wood and adding hardness and pH with stuff like limestone or crushed coral is unnecessary adultering the parameters to an inconsistent soup. Nothing I would recomment.
 
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Rick bose
Member
MacZ said:
The Blog of Tannin Aquatics called "The Tint" is a fountain of knowledge about it. ( ) Otherwise Wikipedia has some quite interesting info. My other sources are in german language, I doubt they are of much use for you.



Test kits. All international companies offer those (Sera, JBL, Fluval, API... pick yourself)



Guppies are by no means softwater fish (They need quite high GH and pH) and I would not even keep them in faux blackwater. You technically can, if the water has high enough pH, but otherwise this is all but a fitting environment for them. But I'm not a Guppy keeper. Or livebearers in general. They are very far from my specialties.



Rocks like those usually bring hardness (GH and KH) and pH to quite high levels and stabilize there.
I would either go for hard water or soft water. Taking the look of blackwater with leaves and wood and adding hardness and pH with stuff like limestone or crushed coral is unnecessary adultering the parameters to an inconsistent soup. Nothing I would recomment.
Ok will definitely look more about blackwater tank and read the sources you suggested. Will try to find more on my own too. And I like guppies but won't them in blackwater tank then. Like you recommended, I won't do that then what I was thinking about like using both wood and leaves to get the blackwater look and then increasing the ph level by rocks. Like you said, it's like meddling with inconsistent soup unnecessarily, I won't do that.
 

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