Dicrossus sexual developement

[TCMontium]

Hello,

The title isn't quite fitting actually. I just wanted to hear about what the sex ratio of your dicrossus batches turned out to be and what you heard from other breeder's batches. And even the ratio you got from juveniles you bought and raised to adulthood.
Right now I have 6 filamentosus and biggest 3 already started to develope forked tails. That means I have 50% males already and the other 3 are 1-1,5 cm smaller than those 3, so there is a high chance I will be having at least 4 males, if not just males…
And in past whenever I read about juvenile filamentosus growing up, people had mostly males (maybe that part is just my luck on reading). I easily found this fiorni thread with mostly males:

https://apistogramma.com//forum/threads/breeding-dicrossus-foirni.14851/

So, what did you experience or read or hear? Did you ever stomble upon a mostly female or 50-50 batch in any Dicrossus species? If so, was the water colder/warmer or ph lower/higher than most people keep their fry/juveniles?

 

[gerald]

I know Finzz has had male-heavy batches of D. maculatus. Maybe he'll chime in and say something about temp and water chemistry. The other issue is that females may grow slower and be less aggressive feeders, so they can get out-competed by their brothers unless there's abundant food.

 

[gerald]

Finzz sent me this in a message tonight: "I've heard from some others that once they spawn, you can unplug the heater and they will hatch more female-heavy as a brood. I don't know if that's true, but it may work. I've never had any luck getting them to spawn unless the temps were in the high eighties."
(I'd probably wait until they're free swimming and eating well for a couple days before dropping the temp. Sex determination probably doesn't begin for a couple weeks).

 

[TCMontium]

I had several spawns in as cold as high 70's to low 80's (25-27 C). Never even tried mid to high 80's before (29-31 C). Maybe the reason all my eggs stayed clear yellow without any developement, than turned white with bubbles inside randomly and instantly, and then just got eaten by the female slowly was the low temps? I blamed the female for possibly not letting males come close and fertilize. Another possible piece for my dicrossus puzzle.

I will keep them warmer this time and lower the temps after fry hatch. (if I even have a female in this group…)

 

[finzz]

Just found the thread- late to the party as usual! I messaged the wrong temps to Gerald- sorry, Gerald; I should have said high seventies to low eighties. I've heard so many reports about these fish being "bad parents" and eating the eggs before they hatch, but I don't really think that's the case. I've raised several different groups of D. maculatus over the years and notice that unless the water is soft to the extreme, the eggs are not viable and the parents will eat them up. If the water is empty of almost all dissolved solids, the eggs are fertilized and the Dicrossus become excellent parents. Just my 2 cents.

 

[TCMontium]

Just found the thread- late to the party as usual! I messaged the wrong temps to Gerald- sorry, Gerald; I should have said high seventies to low eighties. I've heard so many reports about these fish being "bad parents" and eating the eggs before they hatch, but I don't really think that's the case. I've raised several different groups of D. maculatus over the years and notice that unless the water is soft to the extreme, the eggs are not viable and the parents will eat them up. If the water is empty of almost all dissolved solids, the eggs are fertilized and the Dicrossus become excellent parents. Just my 2 cents.

Well then, I had only RO and the aquarium was 15-20 ppm TDS back then when all the eggs would just not develope and slowly get eaten in 2-3 days. I will have to try DI water this time and make it 2-5 ppm TDS.

 

[Bart Hazes]

I bought 1M+2F D. maculosus that turned out to be all males. Later my supplier got a new batch with females and send me three that all developed into males again. So for me it has been a challenge to get females for the maculosus. For D. filamentosus I got 2F+4M from a group of 6.

 

[TCMontium]

I wonder if we are growing the juveniles in too acidic or hot (or even both) water, so they mostly develop as males. But I would guess that the sex is determined earlier than the age we mostly buy them. I am guessing no one tried growing them in 6-7 pH and mid 70s (24-25 C)? I just hope Dicrossus spp. doesn't naturally have a male dominant reproduction strategy.
Low 70s might be too cold for healthy developement, I suppose…

 

[Bart Hazes]

Mine were wild caught. I've had groups of 6-8 wild caught apistos all turning out to be males (agassizii) or females (baenschi). I think it depends on seasonality and plane (bad) luck, but if you buy young fish it is a risk you should be willing to take. Most of the time I get at least one or two of each sex.

 

[gerald]

Well then, I had only RO and the aquarium was 15-20 ppm TDS back then when all the eggs would just not develope and slowly get eaten in 2-3 days. I will have to try DI water this time and make it 2-5 ppm TDS.

15-20 ppm TDS is VERY low conductivity and hardness. It's hard to imagine that would be high enough to interfere with egg fertilization. I'd guess something else is causing infertile eggs, or killing the eggs soon after they are laid. Finzz - thanks for the temperature correction.

 

[dw1305]

Hi all,

Well then, I had only RO and the aquarium was 15-20 ppm TDS back then when all the eggs would just not develope and slowly get eaten in 2-3 days. I will have to try DI water this time and make it 2-5 ppm TDS.

15-20 ppm TDS is VERY low conductivity and hardness. It's hard to imagine that would be high enough to interfere with egg fertilization. I'd guess something else is causing infertile eggs, or killing the eggs soon after they are laid.

If you go for really low conductivity water I would make sure you have plenty of humic compounds as well.

If you have a look at the scientific work of <"Dr Christian Steinberg"> it gives some scientific back-ground. If that link isn't available the original reference is <"Steinberg, C. 2003. Ecology of Humic Substances in Freshwaters: Determinants from Geochemistry to Ecological Niches">.

cheers Darrel

 

[TCMontium]

Hi all, If you go for really low conductivity water I would make sure you have plenty of humic compounds as well.

If you have a look at the scientific work of <"Dr Christian Steinberg"> it gives some scientific back-ground. If that link isn't available the original reference is <"Steinberg, C. 2003. Ecology of Humic Substances in Freshwaters: Determinants from Geochemistry to Ecological Niches">.

cheers Darrel

Thanks for the article. However I couldn't find any correlation between Humic Substances (HS) and conductivity/TDS of the water in the article (I didn't read it completely, but searched for keywords and skim-read for now). Aren't the same amount of humic compounds needed for fishes health both in 0 TDS and in 200 TDS water (when every other parameters are the same, most importantly pH)?

 

[gerald]

Here's another article (no book to buy): http://www.lsu.edu/faculty/galvezf/Publications/galvezetal2008b.pdf
Humic/fulvic/tannic compounds (DOC's) are essential for fish to survive in ultra-soft water. Soft/acidic water without DOC's is lethal.

EDIT: Regarding TCM's question, there's no relationship between humic substances (DOC's) and conductivity because they're not very conductive. You can have a lot of DOC (which would be measured as TDS if you evaporate the water) but it isn't detectable with a "TDS meter" because the meter can only measure the conductive chemicals (mainly ions) in the water. In ion-rich water, the DOC is less important, but can still be beneficial.

 

[TCMontium]

Here's another article (no book to buy): http://www.lsu.edu/faculty/galvezf/Publications/galvezetal2008b.pdf
Humic/fulvic/tannic compounds (DOC's) are essential for fish to survive in ultra-soft water. Soft/acidic water without DOC's is lethal.

EDIT: Regarding TCM's question, there's no relationship between humic substances (DOC's) and conductivity because they're not very conductive. You can have a lot of DOC (which would be measured as TDS if you evaporate the water) but it isn't detectable with a "TDS meter" because the meter can only measure the conductive chemicals (mainly ions) in the water. In ion-rich water, the DOC is less important, but can still be beneficial.

Thanks. I am guessing even if conductivity is around 5-30 mS, if pH isn't too low (for example 5.5), then the DOC levels aren't very important either. Those are the conditions in clearwater streams where apistos like some Apistogramma ortegai and some Apistogramma eunotus are found.

http://apisto.sites.no/page.aspx?PageId=66
http://apisto.sites.no/fish.aspx?fishIndexID=2291&gruppeID=1

Or do these streams contain "lots" of DOC despite looking "clear colored"?

 

[gerald]

Thanks. I am guessing even if conductivity is around 5-30 mS, if pH isn't too low (for example 5.5), then the DOC levels aren't very important either. Those are the conditions in clearwater streams where apistos like some Apistogramma ortegai and some Apistogramma eunotus are found. .... Or do these streams contain "lots" of DOC despite looking "clear colored"?

Did you mean milliSiemens (mS) or microSiemens (uS)? (sorry i cant find the Greek "mu"). 1 ppm TDS is roughly 1.5 to 2 uS (depending on which ions). 5 mS is a LOT of dissolved ions -- equivalent to about 3 grams of salt per liter at 25 C. I don't know whether all of the biologically important DOC's have the distinctive tannin color, or whether some kinds of DOC-rich waters can look clear. But I'd guess that the beneficial effects of DOC's begins at concentrations less than what we can see.

 

[TCMontium]

Did you mean milliSiemens (mS) or microSiemens (uS)? (sorry i cant find the Greek "mu"). 1 ppm TDS is roughly 1.5 to 2 uS (depending on which ions). 5 mS is a LOT of dissolved ions -- equivalent to about 3 grams of salt per liter at 25 C. I don't know whether all of the biologically important DOC's have the distinctive tannin color, or whether some kinds of DOC-rich waters can look clear. But I'd guess that the beneficial effects of DOC's begins at concentrations less than what we can see.

Oops, I meant microSiemens (uS).

 

[dw1305]

Hi all,

Here's another article (no book to buy): http://www.lsu.edu/faculty/galvezf/Publications/galvezetal2008b.pdf
Humic/fulvic/tannic compounds (DOC's) are essential for fish to survive in ultra-soft water. Soft/acidic water without DOC's is lethal.

EDIT: Regarding TCM's question, there's no relationship between humic substances (DOC's) and conductivity because they're not very conductive. You can have a lot of DOC (which would be measured as TDS if you evaporate the water) but it isn't detectable with a "TDS meter" because the meter can only measure the conductive chemicals (mainly ions) in the water. In ion-rich water, the DOC is less important, but can still be beneficial.

That one.

I am guessing even if conductivity is around 5-30 mS, if pH isn't too low (for example 5.5), then the DOC levels aren't very important either.

pH isn't a very useful measurement in very low solute water, it could vary from pH4 - pH8 during a diurnal cycle as levels of CO2 and dissolved oxygen change.

Those are the conditions in clearwater streams where apistos like some Apistogramma ortegai and some Apistogramma eunotus are found.

http://apisto.sites.no/page.aspx?PageId=66
http://apisto.sites.no/fish.aspx?fishIndexID=2291&gruppeID=1

Or do these streams contain "lots" of DOC despite looking "clear colored"?

I think the answer is that they contain humic substances, just less than the black waters do.

They are clear and of low conductivity because they flow across the ancient, very hard, rocks of the <"Guiana Shield">, through very nutrient impoverished soils and there just aren't any solutes that haven't been removed by the rain.

cheers Darrel