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Nijesseni spawn vs cockatoo - question on egg hatching

anewbie

Member
I posted this below in the nijesseni spawn thread but i think it was lost. I have a question in egg hatching. My cockatoo laid eggs and they hatched without any special effort on my part (see picture). My question is does this mean the nijesseni eggs will also hatch in the same sort of water or do they need special water (people in previous thread said they would not hatch unless ph is lowered to 4.5):

b2.jpg
 

dw1305

Well-Known Member
5 Year Member
Hi all,
I think you've answered your own question. Apistogramma cacatuoides will spawn successfully at higher pH and hardness levels than every (nearly every?) other Apistogramma spp.

cheers Darrel
 

anewbie

Member
Thank you. I guess this sort of answer my question. Just because the cacatuoides did spawn successfully does not mean the nijesseni will have success :(

My water is tds 100, gh 7 kh 3 and ph around 7.1 so it is not ultra hard - i just don't have an easy way to improve it for the nijesseni (which are in a different tank with some sterbai).

Hi all,
I think you've answered your own question. Apistogramma cacatuoides will spawn successfully at higher pH and hardness levels than every (nearly every?) other Apistogramma spp.

cheers Darrel
 

anewbie

Member
Not till i move which will be in about 16 to 18 months. Also i'm concern that modifying the ph will cause ph shock everytime i do a water change. I.e, i would need a method to ensure the fresh water has the same ph.

Hi all, Can you mix in some RO or rainwater? It would help soften the water to the state where humic acids from <"Oak leaves or Alder cones"> could depress the pH and hardness.

Have a look at @tjudy's posts in <"How to mimic..."> and <"keeping low pH">.

cheers Darrel
 

Ben Rhau

Member
pH shock isn't really a thing if you're talking about soft water. i.e., the pH of soft water will always fluctuate, sometimes by a lot. The only danger is going from high hardness to low hardness, which can lead to osmotic shock in the gills.
 

anewbie

Member
ok. ALso i was mistaken i only need to go to around 6.5 - it might even be that the ph is fine and i just need to soften the water a little. I was reading on breeding panduro and my hardness seems to be around what they suggest (they suggested 5 to 8 and my water is 7) so maybe just adding 20% osmosis water or rain water would do the job. I can't really do it right now but after I move i'll probably give them a dedicated 20 long to play in (the 29 they are in has a few other fishes). I was just amazed that the caca found a place to spawn and so far seem to be doing a good job guarding the youngs. The male stopped helping but at least 15 frys are still alive - she's in a position i can't help feed the frys so she is on her own ;)
 

dw1305

Well-Known Member
5 Year Member
Hi all,
Also i'm concern that modifying the ph will cause ph shock everytime i do a water change. I.e, i would need a method to ensure the fresh water has the same ph.
Yes it is like @Ben Rhau says you can't really have pH stability in very soft water, because pH is both a Log^10 scale and a ratio you can't extrapolate from hard water (where pH is stable) to soft water (where it isn't). Have a look through <"Water parameters....">.
I was reading on breeding panduro
I think A. panduro is a little less demanding in terms of water chemistry than A. nijsseni for successful breeding, but neither are fish I've kept.

cheers Darrel
 

Mike Wise

Moderator
Staff member
5 Year Member
I've reproduced both species. A. nijsseni is much more demanding with regards to water values. Also higher ph values (above 5.5) tend to skew the sex ratio toward mostly female offspring. This was a problem when A. nijsseni first appeared in the hobby (early 1980's). Hobbyist had hardly any males in their spawns.
 

anewbie

Member
What water parameters did you require to get a good spawn in terms of tds or hardness. I'm not in a position to lower ph right now but after i move i can produce ro water and dillute tap as needed to lower hardness/tds. Given the base is 7 and 100 it would not take too much to get it to 3 and 50. Ph is more problematic. I guess i could put peat moss in the tank or more almond leaves but i think it would take quite a bit.

I've reproduced both species. A. nijsseni is much more demanding with regards to water values. Also higher ph values (above 5.5) tend to skew the sex ratio toward mostly female offspring. This was a problem when A. nijsseni first appeared in the hobby (early 1980's). Hobbyist had hardly any males in their spawns.
 

Mike Wise

Moderator
Staff member
5 Year Member
I would start with water values around 40 µS/cm and pH 5.5 (will vary with such soft water). If this works, keep using it; if not lower the conductivity/pH. I used 35µS/cm and ~pH 5.5. At 79°F/26°C I got roughly even number of both sex.
 

anewbie

Member
The problem is i don't understand the units uS/cm. I've always measured water hardness in terms of GH/KH/TDS. I googled uS/cm but it didn't help much to explain how it relates to water hardness.

I would start with water values around 40 µS/cm and pH 5.5 (will vary with such soft water). If this works, keep using it; if not lower the conductivity/pH. I used 35µS/cm and ~pH 5.5. At 79°F/26°C I got roughly even number of both sex.
 

dw1305

Well-Known Member
5 Year Member
Hi all,
The problem is i don't understand the units uS/cm. I've always measured water hardness in terms of GH/KH/TDS. I googled uS/cm but it didn't help much to explain how it relates to water hardness.
Electrical conductivity is measured in microSiemen/cm, it is a measure of all the ions in solution. It is a linear scale, from DI water at less than 5 uS/cm to full sea water at 53,000 microS. Our tap water is from a limestone aquifer, and about 650 microS, and our rain-water about 100 microS. Water in the Rio Negro would be ~10microS and only the white waters in the Andes piedmont would have many ions of any description.

Total Dissolved Solids (TDS) are measured in ppm, but you can only measure this accurately by evaporating a known weight of water to dryness, and weighing the residue. TDS meters obviously don't do this, they measure conductivity in microS and then use a conversion factor (usually 0.64) to estimate ppm TDS,so 100 microS ~ 64ppm TDS.

There is no direct link between pH (the negative log^10 of the H+ ion activity), dGH (the amount of multivalent cations), dKH (the amount of HCO3- ions) and conductivity, but normally the predominant ions in fresh water derive from limestone (CaCO3), which raises all of dKH, dGH, conductivity and pH.

cheers Darrel
 

anewbie

Member
Thank you! So i want a TDS of approx 25 - or 3 part RO water and 1 part tap (our tap is around 100 TDS). Then use leaves to lower the ph. How do people measure in units of microS ?

Hi all,Electrical conductivity is measured in microSiemen/cm, it is a measure of all the ions in solution. It is a linear scale, from DI water at less than 5 uS/cm to full sea water at 53,000 microS. Our tap water is from a limestone aquifer, and about 650 microS, and our rain-water about 100 microS. Water in the Rio Negro would be ~10microS and only the white waters in the Andes piedmont would have many ions of any description.

Total Dissolved Solids (TDS) are measured in ppm, but you can only measure this accurately by evaporating a known weight of water to dryness, and weighing the residue. TDS meters obviously don't do this, they measure conductivity in microS and then use a conversion factor (usually 0.64) to estimate ppm TDS,so 100 microS ~ 64ppm TDS.

There is no direct link between pH (the negative log^10 of the H+ ion activity), dGH (the amount of multivalent cations), dKH (the amount of HCO3- ions) and conductivity, but normally the predominant ions in fresh water derive from limestone (CaCO3), which raises all of dKH, dGH, conductivity and pH.

cheers Darrel
 

Ben Rhau

Member
TDS is linear, so If you're confident in that your tap is TDS 100 and your RO is near zero, you can accurately predict the result of mixing the two. That said, tap water can fluctuate and RO units have varying levels of efficiency based on method, age of membrane, etc. The simplest way to measure is to get a handheld TDS meter and measure your conductivity directly.
 
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