Rio Negro Darter/Characidium

Youkai · 07-13-03, 09:23 PM

We got in some Darters simply called 'Rio Negro Darters'. They are incredibly inquisitive, interesting, fun to watch fish, and I'm VERY tempted. However, I can't find any information on them anywhere.
I do not know what their water requirements are, nor how to sex them. If anyone knows this info, or can point me in the direction of a super amazing web site, I'd appreciate all of your help.

The ones at work look a lot like this:

<img src="http://www.rva.ne.jp/gallary3/20030322/ca_black_data9681.jpg">

Pic courtesy of:
http://www.rva.ne.jp/gallery/gallary...y_carasin.html

corr · 07-14-03, 07:50 AM

I've been looking all through my bookmarks and doing Google searches with no luck Youkai. Cool fish though! Do you have a Latin name?

Youkai · 07-14-03, 02:49 PM

I'll try and have one tomorrow - when I buy some.

Duncan · 07-14-03, 11:56 PM

I've seen these little guys sold as "hummingbird tetras" before, I guess because the "hover" over their spot of the aquarium and then dart to a new spot (which is why they're more commonly referred to as darter tetras!). Everything I've read about them says that the exact species is often difficult to pin point, but p295 of the Baensch Atlas Vol 2 has a similar picture of Characidium sp. aff. fasciatum, common name, the Rio Negro Darter Tetra. In summary, it says that they need "clear moving water . . . pH 5.6-7.5, hardness to 10 dGH. Coarse gravel substrate with rocks, 2/3 free of plants and the other 1/3 densely planted. The fish enjoys sitting on elevated ground where it supports itself with its pectoral, pelvic and tail fins." I always thought they looked and acted a little like salt water hawkfishes. They are also a lot like the African darter tetras of the genus Nannocharax ( a little convergent evolution for all you biologists out there). In the past, when I've seen them in pet stores, they don't seem to last (and not because people are buying them up!). My guess is that they need fairly high oxygen levels, which would be associated with the "clear, moving water" that Baensch talks about.
Hope this helps a little,
Duncan

Duncan · 07-15-03, 12:06 AM

Oh Yeah,
Baensch Atlas 1, p314, says that males have dots around the base of the dorsal fin and in females its clear. Supposedly, if you find a "compatible pair," spawning isn't that difficult, with eggs falling in between plants and gravel after "free spawning." The eggs hatch in 30-40 hours. This report is for the original C. fasciatum as opposed to the C. sp. aff. fasciatum , but presumable it wouldn't be too far off.
Duncan

Youkai · 07-15-03, 04:37 PM

Hi Duncan, thanks for all the info! I think the only thing I'm sure of is that these aren't the 'hummingbird' tetra species. Those are a bit smaller, and the ones at work also don't really hover. They're more like a cross between a tetra and mudskipper - they hop everywhere!
I think the tank I have would be perfect, but I'll switch the sand to a more coarse substrate.
The ones we have at work are doing amazingly well, and are blast to feed. I'll take pictures of mine when they're set up.

I need to invest in some Baensch atlases

Youkai · 07-20-03, 07:15 PM

Alright, I bought my darters today. They are in a pH of 6.4, lots of water flow (aquclear as well as a power head), lots of driftwood, sand/pebble substrate. Plants are java fern, java moss, pennywort, crystal wort, cryptocoryne (don't know exactly what kind), Hygrophila corymbosa ''Compact'', and a small red lily I don't know the name of. It grows out of a bulb/tuber sort of thing. The leaves are a pink/red color.

Tank mates are green barred danios, and a dwarf hoplosternum. I'm going to try tying down some of the riccia (crystalwort) soon.

Oh, and these guys are nuts for snails. They hunt them like a cat hunting a mouse, and really go nuts!

corr · 07-20-03, 07:45 PM

Sounds like a great setup! Good luck with them!

Duncan · 07-20-03, 11:31 PM

Does sound like a super setup, I'd love to see pics when you have a chance. By the way, what are your green barred danios (latin name?)? They sound interesting.
Duncan

Youkai · 07-21-03, 12:57 AM

Hey Duncan!

<i>Barilius pulchellus</i>

Here's a picture:
http://store3.yimg.com/I/ekkwill_1746_34875307

They don't seem to like our store water, even though it's quite decent. But the ones I took home have doubled in size and are just gorgeous. They are insanely active but don't touch other fish. In fact, I have a lone white cloud who swims with them.

I've seen max size listed at 2", but I have one at 2.5" and I believe it's still growing...
Oh, and their mouths are HUGE. I feed them small cichlid pellets with ease!

Shane Tesser · 07-22-03, 08:00 PM

They attack snails! Interesting, ill try and get some of those now!!! Keep us updated Youkai, those are very cool looking fishies

Darlene · 07-23-03, 08:23 AM

Eat the snails ?! omg!! An answer to my prayer's !!! Did you get their Latin
name yet, Youkai ? I'm with Shane & want some now !! My clown loaches have helped with the snails but I haven't the heart to starve them into it very often. These guys would be a more then welcome addition.
Anxiously awaiting more news, Dar.

Youkai · 07-23-03, 11:14 AM

Darlene,

The closest I've gotten to identifying them is the unidentified <i>Characidium sp. aff. fasciatum</i> name that Duncan grabbed from his Baensch atlas.
Seems to me they are being imported under the name Rio Negro Darter at the moment. Maybe ask a few stores in the area if their suppliers carry them, and if they will order them for you.

Darlene · 07-24-03, 09:52 AM

Thanks, Youkai. I'll have a go at it & see what I can get.