Sexing clown loaches

[Coryloach]

I've read everything I came across over the years but I can't remember reading in any English translated paper about the actual act of spawning or that eggs float? That's a first to me.

But I think I know which paper your have in mind. It was more on the eggs and fry development and best conditions if I remember correctly. Most of the latest scientific papers seem to be done on clown loaches from Sumatra for some reason...

 

[RD.]

It wasn't a paper, it was a power point type presentation, with enough data and photos to sink a ship. I actually found the link, it was in my Kalimantan vs Sumatra sticky, but unfortunately it's now a dead link. It showed gravid females, I believe the researchers milking males, the holding tanks, eggs/larvae/fry, the hormones used, etc. The entire thing was in English. Dang, what a bummer, I should have tried to save it.

https://www.was.org/documents/MeetingPresentations/AQUA2012/AQUA2012_0621.pdf

 

[Coryloach]

That's a pity. Perhaps it's somewhere else on the net. I'll try searching a bit as some definitive pictures of males/females would be handy right now...

 

[Coryloach]

Today I also came across a study on "The potential of Artemia-mediated delivery of
a gonadotropin-releasing hormone analogue to induce ovulation in the cardinal tetra"

Since Gonadotropin is used in clown loach hormonal breeding via injection, manualy stripping, etc..., why hasn't anyone attempted to enrich some artemia with the hormone and feed it to clown loaches and let them do the job naturally?

Here's the link:

https://www.researchgate.net/public..._in_the_Cardinal_Tetra_Paracheirodon_Axelrodi

Obviously, the fish need to be sexually mature and gravid but that doesn't seem to be the problem in clown loaches...

 

[RD.]

This wasn't what I was looking for, but as far as I'm concerned is far more trustworthy than a breeder in Russia, with a much higher count for test subjects. And this is exactly how I recall that power point presentation, the researchers "milked" the fish to ID males.

https://www.researchgate.net/public...ction_in_two_populations_from_Sumatra_and_Bor

In total, 196 sexually mature fish, of unknown age, were

used in the induced breeding experiments: 112 females of

46−404 g body weight (BW) and 84 males of 15−180 g BW.

No clear sexual dimorphism was apparent. Males were identified

when sexually mature by the emission of sperm upon gentle

abdominal hand-pressure and females when oocytes could be collected by

intraovarian biopsy.

 

[RD.]

My only real interest in breeding clown loaches was the hope that someone could figure out a cost effective manner in which millions could be produced for the export trade, without the collection of wild fish.

 

[Coryloach]

Yes, but at the same time they did notice body changes in maturing females:


Ripe females (i.e. ready to reproduce) were
selected on the basis of three types of criteria: the degree of
abdominal stoutness, the distribution of follicle diameters and
the position of oocytes’ germinal vesicles (GV). The degree
of abdominal fullness was considered for fish from group 2
only. It was always estimated by the same observer, who
ranked the fish into one of the three following categories:
(1) no particular stoutness, (2) noticeable stoutness or (3)
important stoutness with rebounded and soft abdomen.

 

[RD.]

Not exactly what I was looking for, but close. This is where all the real hard core CL breeding has taken place over the past decade.

https://www.scribd.com/document/295068920/Loach-Breeding-pdf

 

[RD.]

Yes, there's no argument there, clearly anyone that has owned a large group of clown loaches can spot a sexually mature female. The argument was in regards to fin length/shape, etc. If there were any discernable differences these gents would know, they have handled and bred more wild caught CL's than the rest of the free world combined. lol

So I think that's is safe to say, fin shape, fin length, fin anything, is bunk with regards to sexing a CL.

 

[Coryloach]

I am inclined to agree....

The pelvic fin of my mature gravid female is larger than that of any other clown loach I have. The fish is also older than any of my other clown loaches, and the biggest in the tank....So although I am quite certain she's a female and I am quite certain about 3-4 males in my tank, this female still has the largest pelvic fin If other fish were of the same size, then maybe....

Having said that, the trio of the Russian breeder is almost of identical size/length and I can distinguish the shape difference between the males and the female on his youtube video, although I can't quite see any pelvic fin differences..