Sexing Dicrossus sp. "Rio Negro"

[Quixotic]

I have just gotten hold of some Dicrossus sp. "Rio Negro" recently.

There don't seem to be a lot of information on these fish from the Internet, aside from citation of some published literature. Unfortunately, I do not have any of the literature either, so I am having some difficulties in identifying their sexes.

However, I did manage to track down a Spanish language website with some information. As the following information was done over translation tools from the Internet and (mis)interpreted to my limited knowledge, can someone please share his/her views if these are applicable with regards to their sexual dimorphism?

1. Adult males - round or lanceolate caudal fins. Females - round caudal fins.

2. Males - caudal fins with purple and green flashes(?). Females - transparent caudal fins.

3. Males - red outer edge, black markings/spots in dorsal fins. Females - red outer edge, lacking black spots in dorsal fins

4. Males - anterior(?) and posterior dorsal fin tips are pointed. Females - rounded fin tips.

5. Males - pointed anal fins. Females - rounded anal fins.

The fishes are approximately 3.5 to 4 cm SL. Are we able to tell their sexes at these sizes?

Many thanks.

 

[Apistomaster]

Hi Quixotic,
You have a special little fish there and one for which there is little documentation except it has bred successfully in captivity, with water conditions as per generally recommended for the Genus but I would think the lower end of values will suit them best and organic substances extracted from peat, oak leaves the ubiquitous Keta pang almond leaf are all well worth added to their tank and water as long as the conductivity, pH are very low. pH of 4.0 is not to low and less than KH of 1 is plenty if not too high. This makes management of stable conditions very difficult but I believe that is where one should begin with any attempt to raise them in captivity. I wish you success and hope to read about it here.