Dicrossus sp. "Rio Negro"

[illumnae]

Any updates? I found pictures of possible males:

http://apistogrammaidiots.com/Fishro...4-rionegro-m-2

[doppelbanddwarf]

Mine have just grown bigger. Other than that no change from when I first got them.

[Quixotic]

Any updates? I found pictures of possible males:

http://apistogrammaidiots.com/Fishro...4-rionegro-m-2

Ah, I have seen the pictures before and yes, could be males, the anal fin looks pointed and the tail is spade-like more than rounded. But are these the same species as these are marked with a "?" behind?

Mine have grown up a lot. Here's the catch, some have stayed the same size when I first got them (maybe slightly larger), while some have doubled the size. Yes, it's double the size. Can these be signs of sexual dimorphism? Otherwise, how can there be such a huge difference in size?

Aside from the size, the larger ones seem to be more colourful (more patterns on the fins) than the smaller ones, but they do not look like the supposedly males from the pictures in the URL posted by illumnae. Anal fins aren't extended, caudal fins are rounded.

I may be missing something because my assumptions seem to be contradictory.

Based on the size, the assumption is that: larger = female, smaller = male
Based on the pattern/colour of fins, the assumption is that: larger = male, smaller = female
Based on fin features, the assumption is that: larger = smaller = female

Unless someone else has other insights, I think there may be some more growing to do in order to strike out some of the assumptions.

[illumnae]

what's your water conditions like Quixotic? Perhaps drop your ph to 4.5-5.5, very low TDS, low lights and lots of leaf litter. hopefully these guys share the same spawning requirements as the other Dicrossus sp. and will spawn for you, then you will know for sure which are male and which are female

[apistomaster]

I think you will find this species takes some time to reach maturity and maximum size is going to be slightly larger than common Dicrosssus filamentosus. Fully mature specimens will exhibit sexual dimorphism; males are larger than females of the same age class and more well developed in fins and colors. In the book, South American Cichlids by Dieter Bork and Hans J. Mayland, they write that females that have spawned developed yellow vental fins.
I haven't had the pleasure of keeping this species myself, but I do have friend who has a group. His are also still not fully mature so I haven't heard any further first hand confirmation regarding the color change of the ventral fins after spawning. I wish him and you all success in breeding this species.

[Quixotic]

Thanks for the information apistomaster.

Interesting... then the bigger and more colourful fishes that I have, could still very well be males. I will see if I can post some pictures and statistics on current sizes.

[Quixotic]

Some new photos of the fish. Pardon the quality and reflected glare on those photos where flash is being used.

The larger fish is around 6 cm SL, and the smaller fish is around 4 cm SL.

Just for comparison between larger and smaller fish, without flash.


Comparison between larger and smaller fish, with flash. The larger fish has obvious colours and patterns on the fins, while the smaller fish is rather plain.


Smaller fish, no obvious colour or pattern on fins.


Larger fish, obvious colour and pattern on fins.


Larger fish, with flash.

[leeruisheng]

Hopefully you've got mixed sexes. But to wonder were there any flarings going on among them?

Came across basil website and saw some new photos.

[Quixotic]

Thanks Wilson. Well, there is some form of flaring, most of the time among the larger fish, but smaller fish are sometimes involved. Also, the "flaring" is for a short while only, more like chasing away another fish. Oh well...