Dicrossus gladicauda

[merlin]

Got 5 small specimens of this species from Holland. Ive read the species description but does anyone have any experiences they could share with this species. A couple of record shots below.

 

[Mike Wise]

If these are D. gladicauda (I can't be sure from these photos) then treat them like the Orinoco populations of D. filamentosus with soft and acidic water conditions.

 

[merlin]

Thanks Mike. Im not certain of ID. They were sold as gladicauda but time will tell. The fish are only 15-20mm TL. Dont know if there is anything that can help with ID in these young fish.

 

[aquaticclarity]

The one time I brought some in they were tiny and desperately in need of food. And after 4-5 months of growing out they turned out to be D. filamentosus! I hope you have the real deal!!!

 

[merlin]

Aquaticclarity do you know what to look for as early indications to being D. gladicauda.

 

[aquaticclarity]

Aquaticclarity do you know what to look for as early indications to being D. gladicauda.

Nope. As far as I can tell they look alike other then the single versus double tail spike. But that doesn't mean there aren't some other differences. I haven't seen the fish in person yet, just some low quality pictures, so I'd guess there might be some noticeable features you could use to tell the two species apart.

So please keep taking pictures of your fish every month or two!

 

[merlin]

Some new pics of the D gladicauda

 

[gerald]

Are those pics 4 different fish, or all the same fish? They (it?) look like females.
I sure hope they're glad's. The body looks a bit higher and chunkier than most fil's.

 

[Mike Wise]

It will be interesting to see what these juvenile will look like when mature. Juveniles, and apparently females, can't be separated from juveniles/females of D. filamentosus. From the original description (underline mine):

"Dicrossus gladicauda is most closely related to Dicrossus filamentosus. Both species are very similar and cannot be separated by proportional or meristic characters, but differ significantly in the shape and colour pattern of the caudal fin of adult males."​

This is why many knowledgeable people have problems with this species. It occurs in the same river systems where D. filementosus is also found. Is it really a different species or just an odd variation of D. filamentosus?

 

[merlin]

The pics are random pics of the 5 I have. One is definitely larger than the others and is chasing the others about...male perhaps. Was looking at some pics online and they showed filamentosus with 6 spots along the lateral line and gladicauda has 7. Is this random or are there differences.

 

[merlin]

Sorry the comment about the spots is the wrong way around. Filamentosus has 7 spots and gladicauda 6 spots

 

[Mike Wise]

Random, I guess. There is no difference between the 2 species in body shape, fins, or pattern except on the caudal fin of the male, according to the original description.

 

[gerald]

In their 2008 published description of D. gladicauda, Schindler and Staeck state: "In spite of the overall similarity between D. gladicauda and D. filamentosus, we describe the new form as a separate species and refrain from using a subspecific category for we agree with Kullander (1999, 2004) that every single diagnosable form deserves its own specific treatment.”

In other words, it looks different so it must be a distinct species -- a faith statement, not science. That seems like a pretty cheesy excuse for a species description IMO, and I'm surprised it made it through peer review. I would like to know if the captive-bred males all show the "gladicauda" tail type. At least that would give a little evidence that it's not just a polymorphic trait like agassizi color varieties.

 

[Microman]

If they do indeed turn out to be D.gladicauda it will be a first timer in the UK... We had what some thought were gladicauda in 2006-07 but these turned out to be filamentosus. The fish you have were unbelievably cheap for a fish that, i would have thought, they would have wanted to make big bucks from.
Good luck with them and fingers crossed...
Mark...

 

[Microman]

Sorry the comment about the spots is the wrong way around. Filamentosus has 7 spots and gladicauda 6 spots

I thought this was the difference between the Orinoco and some Rio Negro forms of D.filamentosus.
Mark...

 

[merlin]

You maybe correct microman I googled the two species and was comparing the photographs submitted for both species. There was nothing to say what race the filamentosus were.

 

[Yo-han]

Without naming the shop I guess you got them from Amersfoort. I got 5 as well and seriously hoping they are gladicauda, but like yours, still too small to sex. I believe I've 3 females and 2 males. They are all doing fine in my planted tank for a few weeks now. Not very soft or acidic (KH:6 pH 6.4 with CO2), but happily foraging around. Schooling together from time to time. But I couldn't see any differences with the filamentosus too. They are eating eagerly so I guess they mature quite fast!

 

[merlin]

Yo-han I believe my fish came from the shop Utaka. A lot of different fish were bought all of a good quality.

 

[merlin]

Mike at what age would you think the sword would begin to develop. I know we dont know how old the young are but it will help give me an age working it back.

 

[Microman]

At 6 months you should be able to tell what you have...
Bear in mind that on substrate dwelling species the bottom swords often dont develop as quickly as top swords
when the caudal is constantly in contact with substrates.
Ive often found this to be the case with Biotoecus but they tend to spend much more time at substrate level than Dicrossus.
Mark...