Anyone can teach me how to identify sex of Notho?

[keehoe]

Hi all, is there any other way to identify the sex of the Notho without considering its colour? I suspect some of my Notho. Korthausae are actually female but having full colour on. In my setup, even Notho. Rachovii Nicuadala 04-10 female started to develope colour. Maybe is the food that i have been feeding them?

[stormhawk]

Kee Hoe,

Most Notho females are by far easily sexed from the males by means of colouration.

Exception being the females of N. fuscotaeniatus, which also have the criss-cross barring on the sides.

If the females are developing some sort of enhanced colouration then its probably due to diet. If you fed astaxanthin to your fish then probably the females would develop slight pigmentation on the body.

Then there are subdominant males which are somewhat pale in comparison to the dominant males. They may look like a "female" at times.

[RonWill]

Exception being the females of N. fuscotaeniatus, which also have the criss-cross barring on the sides

You mean this?

[stormhawk]

Yes Ron that was much appreciated. In that picture those with a silvery-grey base body colour and a faint banding pattern is the females.

[keehoe]

But my female Rac is developing not only red pigment but the black marking as well I know they are female because i ever collected egg from them before. Just that not viable. Is that the sign of aging?

I have yet another fish (not sure male or female) but i have never get any egg from these "pair" so i suppose it is a sub-male. But i have a feeling that it is a female judging by its body shape. Male normally have "sharper" look, while female have a rounded head.

Yesterday when i try to feed my Korthausae, i really two of the smaller fish have blowed body. Normally the alpha-male would be the first fish that get itself blowed as it ate the most. The two smaller fish also have clear tail. (Korthausae male have tiger mark on its tail.) Anyway going to try spawn them tonight as i think almost all fish will colour up in my tank male/ female. I will try to switch their diet and see if the differences turns more obvious. Else i really have to Mini-Maini-Mor.

Anyway, for the breeding pair / female fish i don't normally feed them Asthaxanthan. Only brine shrimp enrich with lots of spirulina.

[erikthur]

But my female Rac is developing not only red pigment but the black marking as well I know they are female because i ever collected egg from them before. Just that not viable. Is that the sign of aging?

I had a similar experience. A small RAC that looked like a female for some months and then slowely shifted to male coloration.
However, I don´t know if that fish laid eggs or not - no other male present.
Later, I got eggs from this fish and two females. But I don´t know yet if they were fertile or not.
I hope it was a true late male bloomer.
Or do sex change occur among killies like in swordbearers?

[TyroneGenade]

Nothos are easily sexed by the shape of their anal fins.

See http://home20.inet.tele.dk/fcl/tan98/ann12f.jpg (female) and http://home20.inet.tele.dk/fcl/tan98/ann12m.jpg (male). The anal fin of the female is more spade shaped while that of the male is more like a fan. Even in that picture of the fuscotaeniatus you can see the "dull" fish have a more angular anal fin than that of the males as can be seen at http://www.killi.co.uk/SpeciesDetails.php?ID=453.

What foods are you feeding? They may be contaminated with steroid hormones.

tt

[erikthur]

Nothos are easily sexed by the shape of their anal fins.

Hello tyrone,
How early can you sex nothos by the anal fin?

[keehoe]

Spot on Tyron. I feed them adult brine shrimp enriched with spirulina. Occationally enriched with a product call C.R.6 from a company call White Crane. On the label: "A new vitamin with carotinoide for feeding to red color fish. such as arrowana. red gourami, oscars, red discus, gourami, goldfish, carp etc. Fish will eat and grow well. Theis product does not contain sex hormone". Sometime Hikari frozen blood worm also.

The spirulina i bought is from health shop, they claim 100% pure spirulina.

[TyroneGenade]

I'm afraid I can't give you a definative answer Erik.:-( It varies from species to species. For fruzeri it is at 3 weeks! For kilomberoensis I was still guessing at 6 weeks.

tt

[nonamethefish]

So this Nothobranchius kafuensis is a female?





The code is 'Kayuni' ZAM 97/9. Doesn't seem like very many keep this population as I have found hardly any references to it.

[erikthur]

But my female Rac is developing not only red pigment but the black marking as well I know they are female because i ever collected egg from them before. Just that not viable. Is that the sign of aging?

I had a similar experience. A small RAC that looked like a female for some months and then slowely shifted to male coloration. However, I don´t know if that fish laid eggs or not - no other male present. Later, I got eggs from this fish and two females. But I don´t know yet if they were fertile or not. I hope it was a true late male bloomer. Or do sex change occur among killies like in swordbearers?

I checked the eggs today and found one eyed-up egg at least.
I will now wet my RAC peat
Thus, He was a true late bloomer.
It took him more than 10 weeks to show his colors.

[TyroneGenade]

Kafuensis "females" younger than 8 weeks have a nasty tendancy to turn into males so I'm not going to render any opinion on the sex of that young fish.