Congochromis dimidiatus

[rasmusW]

Hi all!

i got a free tank and is debating heavily with myself, about what to put in it.
One of the fish i have been thinking of is this.
Therefore i’d like to hear about your experiences with it.
disclaimer:,i have never kept West african fish, so here is a few questions i couldn’t find answers to…
-is it suitable for a 75 liter tank?, should i get only one pair or more? -maybe a harem, how large are their spawns?, i am thinking of normans lampeye or jae barbs as dither. Are they suitable?

looking forward to hear your thoughts.

-r

 

[Mike Wise]

I really cannot give you any advise since I never kept them. My only question is where do you acquire the true C. dimidatus?

 

[MacZ]

Aquarium Glaser has had different Congochromis several times between 2016 and 2018. Ruinemans had C. dimidiatus in 2019, so there should be some degree of availability in Europe these days.

 

[rasmusW]

Hey guys!! Thanks for getting back.
MacZ is correct. Ruinemans have them at the moment. Wheter or not it’s the real deal, i can not tell. The picture on their site isn’t the best either.
They also had them back in 2019 or so.
It was back then i got a bit of interrest in them.
I do have other ideas for the tank, that i’d like to explore aswell. So basically, i’m just curious.

-r

 

[rasmusW]

Hey!!!
i thought i should update you here. I went a completely different route and is now owner of 6 parosphromenus linkei. Still not sure of their sex, though. It’s sure a completely new fish adventure…

-r

 

[MacZ]

parosphromenus linkei.

Ooookay... First league of blackwater fish. I don't dare touching licorice gourami of any kind. Respect.

 

[Tom C]

As I am constantly preparing extreme blackwater for a few of my Apistogramma, there is always room for a few Parosphromenus in one or two of my smaller tanks.
Exciting fish, Rasmus! I don't keep P. linkei right now, but I kept them a few years ago:

I wish you good luck with them!

 

[rasmusW]

Ooookay... First league of blackwater fish. I don't dare touching licorice gourami of any kind. Respect.

Thanks Mac! I was honestly also very hesitant about it. Little fish with fairly demanding needs… luckily they seem to be doing fine. There is a lot of microworms and whatnots for them to feed on. I try my best to keep adding more.

As I am constantly preparing extreme blackwater for a few of my Apistogramma, there is always room for a few Parosphromenus in one or two of my smaller tanks.
Exciting fish, Rasmus! I don't keep P. linkei right now, but I kept them a few years ago:

I wish you good luck with them!

thanks a lot Tom!
ye! They are sure fun to watch. I am debating (with myself) whether or not i should add other fish or just keep it as is. I am aiming at spawning them, so maybe other fish is a bad idea.

which species do you keep now?

-r

 

[MacZ]

I am debating (with myself) whether or not i should add other fish or just keep it as is.

I don't know at what pH you keep them, but isn't there only a limited number of possible tankmates available anyway?

 

[rasmusW]

I don’t trust my pH meter, so i actually don’t what it is atm.
And yeah! I have been thinking of chokolate gouramies, a small rasboa (like bigitae) or sundadanio axelrodi. The two last ones could potentionally be fry predators and i’m not sure if the tank is big enough to also house chokolates. Maybe one of the smaller bettas.
i’m not rushing it so time will tell.

-r

 

[Tom C]

which species do you keep now?

I only keep Parosphromenus nagyi now

 

[MacZ]

I don’t trust my pH meter, so i actually don’t what it is atm.

Below a certain TDS/EC a pH-meter isn't going to work anyways. Mine quit working below 60mg/l TDS/roughly 120µSI/cm EC, even though it is perfectly calibrated and works fine in clear- and tapwater. But my blackwater tank... Only thing that works halfway decent is a driptest that goes down to 3. But that one also says, with KH below 3° it's less accurate than it would be normally. So my best bet to keep pH checked is actually observing the fish and plant growth.

 

[dw1305]

Hi all,

Below a certain TDS/EC a pH-meter isn't going to work anyways. Mine quit working below 60mg/l TDS/roughly 120µSI/cm EC, even though it is perfectly calibrated and works fine in clear- and tapwater.

<"ISFET (solid state) pH meters"> will work at lower conductivity values. The other option is to add a "neutral salt" (like sodium chloride (NaCl)) to a water sample to raise the electrical conductivity.

But that one also says, with KH below 3° it's less accurate than it would be normally. So my best bet to keep pH checked is actually observing the fish and plant growth.

I'd actually use a conductivity meter and aim for less than 50 microS, if you can get water that low in solutes an <"addition of tannins"> should reduce the pH down well below neutral.

I don't keep any extreme black-water fish, this is because I'm a rain water user and our rain water <"has enough carbonate buffering"> to preclude them from breeding successfully.

cheers Darrel

 

[anewbie]

I don't keep any extreme black-water fish, this is because I'm a rain water user and our rain water <"has enough carbonate buffering"> to preclude them from breeding successfully.

cheers Darrel

Not to be naive but how does rainwater fall with carbonate buffering ?

 

[MacZ]

<"ISFET (solid state) pH meters"> will work at lower conductivity values. The other option is to add a "neutral salt" (like sodium chloride (NaCl)) to a water sample to raise the electrical conductivity.

I know those meters. Far outside my budget. But the salt would likely do the trick.

I'd actually use a conductivity meter and aim for less than 50 microS, if you can get water that low in solutes an <"addition of tannins"> should reduce the pH down well below neutral.

You misunderstood. The instructions of the drip test I use say the results are not reliable when KH is below 3°.
(btw according to said test my pH is at 4.5). I (obviously) use a TDS/EC-meter anyways. Watching fish and plants is to determine whether it's too LOW, not too high.

Not to be naive but how does rainwater fall with carbonate buffering ?

Carbonate has the chemical formula CO3. Being exposed to air (which contains O2, CO and CO2), with maximum surface as a rain droplet water can take up stuff from the gasses. So it can technically contain CO3 due to solved CO2, which is solved in water as H2CO3. And behold: That's H2O + CO2.
But: Rainwater doesn't always contain carbonates. If you let it sit long enough to gas out CO2, most of the buffer is gone.

 

[rasmusW]

Hi all,

<"ISFET (solid state) pH meters"> will work at lower conductivity values. The other option is to add a "neutral salt" (like sodium chloride (NaCl)) to a water sample to raise the electrical conductivity.

I'd actually use a conductivity meter and aim for less than 50 microS, if you can get water that low in solutes an <"addition of tannins"> should reduce the pH down well below neutral.

I don't keep any extreme black-water fish, this is because I'm a rain water user and our rain water <"has enough carbonate buffering"> to preclude them from breeding successfully.

cheers Darrel

I too use rainwater, though i do not know any of the values i have succeeded breeding a. Atahualpa. A true blackwater species for the more acidic waters (-but that i don’t have to lecture you on).

i hope that i can lower the pH far enough and keep it fairly stable.
I ended up with p. linkei, because as far as i could read, they can thrive and spawn at pH values not too crazy low, they should be a good beginner and lastly, they are damn pretty fish.

I only keep Parosphromenus nagyi now

those are also very pretty.

btw. I have just about one of the newly discovered species. Can’t remember the right now, but was interresting about it was the fact that caudal fin shape was more or less different in each individual. From rounded to centered enlongated filament. Colors and pattern also varied a lot, even in neutral mood.
Does there exist apistos where both fin shape and colors varies like that?

-r

 

[rasmusW]

Here is the article i was talking about..

parosphromenus kishii – The PAROSPHROMENUS PROJECT

parosphromenus-project.org

-r

 

[Mike Wise]

A. elizabethae has at least 2 color populations and the caudal can be either spade/lance or lyre tail shapes.

 

[rasmusW]

Could these differences also occour in the same spawn of A. Elisabethae? As i understood the article i linked, this was the case.
A mixed bag of goods, if you will.

-r

 

[dw1305]

Hi all,

but how does rainwater fall with carbonate buffering ?

It is a good question and I assume it probably picks it up from lime containing dust, either in the atmosphere or on the roof.

The chemistry of calcium carbonate (CaCO3) is a a bit strange, it is "insoluble in water, but soluble in weak acids", and a very large amount of surface fresh water is saturated with both Ca++ and 2HCO3- ions ("hard water").

The reason for this is that rain water is naturally slightly acidic, purely because a very small proportion of CO2 goes into solution as carbonic acid (H2CO3).

This H2CO3 disassociates into a bicarbonate (HCO3-) ion and a proton (H+), and, as acids are <"proton donors">, the pH falls.

When the rain falls onto a limestone containing substrate a small amount of limestone is dissolved and the pH rises. This carbonate ~ CO2 ~ pH relationship is how you get hard water, stalactites, tufa, travertine, caves etc.

I live in the <"S. Cotswolds"> and there is quite a lot of <"limestone mining locally">. If I collect rain water after it has snowed it will be down to <30 microS, in the late summer, after they've cut the corn and ploughed the fields, well over 100 microS.

cheers Darrel