Suggestions For My 50Cm Cube Tank

[Matt141980]

Hi, I'm new here and looking for some suggestions for what my best choice of fish would be for my 50cm cube tank. At present I have 6 zebra danios in there and that's it. I had issues with the PH dipping to below 6 last year and ended up losing all my fish except the zebras who carried on as if nothing had happened.

I'm wondering what to put back in there with the zebras this time round? I quite like Bolivian rams but not sure if I have the space?

My water is very soft so I have used a little crushed coral in the filter to stabilise things. Current readings taken with API master kit are:

PH 7.8
Nitrate, Nitrite and ammonia all 0
KH around 1 (hard to tell as first drop changes colour)
GH 4

I'm not sure if I need to maybe add a bit more coral and bring the hardness readings up further?

Any suggestions / advice would be much appreciated.

Matt.

 

[Jeremy180]

Okay, for anyone else from the US replyiing here, a 50 cm cube aquarium is about 18 inches, and 25 gallons (95L).
I'm thinking that a bolivian ram would be chancy in a tank this size, cichlids like their "elbow room" and can get violent if they don't have enough space.
I think you might have enough room for a pair of cockatoo dwarf cichlids, but don't quote me on this.
Alternately, a pair of Peacock gudgeons might work, although i'm not 100% sure the water is hard enough for them.
As for any other fish, many cory species would appreciate this hardness, as well as most, if not all tetras, and many of the danios/rasboras, although I would strongly suggest sticking to the smaller species with your size tank (IE: under 50mm/ 2 inches).

 

[Munroco]

Sorry to disagree Jeremy, but a PH of 7.8 definitely will NOT suit cories, most tetras, Apistogramma species. They are all more comfortable around 6.5 although 7.0 isn't too bad.

 

[StevenF]

Maybe a school of celestial Pearl Danios.    they are slightly smaller that zebras.

 

[OldMan47]

I think I would reduce the amount of material in your filter and let the pH drop closer to 7.0. You have very soft water so you will be looking for some of the "black water" fish from the Amazon as your main stocking. With the top area of your water already busy from the zebras, how about a nice stocking of 6 or so of a single cory species? In a group they are very active and almost as playful as the zebras.

 

[Matt141980]

Thanks for the suggestions. I only have a very small amount of crushed coral in the filter at the moment but will try taking half out and see if the PH falls a little.

I was under the impression that a stable PH was more important than the actual number and most farm bred fish would adapt to a wider range?

 

[Jeremy180]

Thanks for the suggestions. I only have a very small amount of crushed coral in the filter at the moment but will try taking half out and see if the PH falls a little.

I was under the impression that a stable PH was more important than the actual number and most farm bred fish would adapt to a wider range?

 
About that, there seems to be a common misunderstading between hardness and PH, one that I admit being a victim of myself until recently...
I believe a  it could be somewhat worded as a chicken or the egg scenario except this one has a definite answer, which is explained quite well in post 20 of this thread, the link to which I found in OldMan47's signature.
http/www.fishforums.net/index.php?showtopic=203935
To make a long story short, while hardness and Ph are related values to a degree, they have very different levels of importance to the fish.
As stated by matt, a stable Ph is more important than the actual number, with most farm bred fish being somewhat adaptable,
Hardness on the other hand, is a much more critical parameter, and should be followed as closely as possible, with only slight if any, leeway being given for farm-raised fish.

 

[OldMan47]

A stable pH is indeed more important than a "correct" pH. The crushed coral is a chemical water treatment that you are using. Reducing it will help your tank be more stable. If you actually do have low pH very soft water, why not work with it instead of trying to raise the pH? That is where the "black water" stocking makes sense.

 

[jag51186]

Is your water softened through a water softener Matt?? If you have what is likely a zero KH, and a GH of 4 with crushed coral added, I would guess that it might be. My water is softened and comes from tap at 0 KH and 0 GH, so I used it directly from the well source for awhile instead (6 GH/3KH), and now use remineralized RODI water. Was just wondering because softened water isn't ideal for fish/plants, but you can use a different softening salt to make it mildly better (potassium-based I think?)
 
To the other knowledgeable folks that have commented...would it be worth him adding a little KH into the system with a touch of Baking Soda to prevent wild pH swings? Could also add GH booster to your water change water instead of using crushed coral, which would allow you to basically pick what GH/KH you want to be at. It's similar to remineralizing RO water.

 

[NickAu]

 
A stable pH is indeed more important than a "correct" pH. The crushed coral is a chemical water treatment that you are using. Reducing it will help your tank be more stable. If you actually do have low pH very soft water, why not work with it instead of trying to raise the pH? That is where the "black water" stocking makes sense.

+1

 

[Matt141980]

Hi all,

My tap water is naturally very soft as it comes from the tap and isn't softened any further by me or the water company. My only reason for using the crushed coral was to try and stabilise the PH and avoid the drastic PH drop I had experienced before.

I'm certainly not against working with the water as it comes from the tap, I just want to avoid the disaster I had before where the PH dived and killed off all my filter bacteria causing a spike in ammonia. Are the commercial hardness buffers safe to use? Any side effects I should be aware of?

 

[OldMan47]

I usually avoid any chemical treatments, including pH buffers. Have you looked at stocking things like neons, angels, rams, corydorus and such instead of changing your water parameters? These fish are not necessarily compatible with each other but may give you ideas on a direction to go with soft, slightly acidic water rather than try to make your water more like my high pH hard water.

 

[NickAu]

Most people I know would kill for soft low PH water