N. trifasciatus or N. marginatus?

**Czyne** · 30th Mar 2009, 12:53

Does anyone here know any tell-tale differences between the two? From everything I've read so far, marginatus has no red in the caudal. Is this an accurate trait to go by? If so, is it the only one? If anyone has links to scientific descriptions or anything else of interest, they'd be greatly appreciated also.

Tried to get a photo of the fish in question, but am terrible with focusing close-ups of things that don't sit still for long. Here's the best of the blurry shots:

Little bit of yellow in the anal fin; red in all fins other than pectoral and caudal. No white on any of them. Top two black lines extend partially into the caudal fin. Red stripe above the middle line doesn't even cover 1/4 of the body length. Not sure if any of those facts are helpful indicators.

Basically wondering because I'd rather not have dithers that get potentially bigger than my upcoming apistos

**CK Yeo** · 30th Mar 2009, 13:06

Colours are not a good indication since they vary a bit depending on where they were collected. Main difference for me is the size.

ck

**Czyne** · 30th Mar 2009, 13:17

Thanks CK. Size is not going to work yet if you mean length-wise as they are still young and smaller than a full-grown marginatus. Is there any other way to tell? Have also heard that marginatus is "fuller bodied" than the trifasciatus, but from those photos you posted that doesn't seem to be a very good indicator either.

**barmby** · 30th Mar 2009, 14:54

The indicator for me will be N. Trifasciatus is a longer fish with slim body while N. Marginatus is puny, always smaller and rounder than Trifasciatus

**Matt Ford** · 30th Mar 2009, 19:00

Hi Czyne although a clearer shot would help I'd say the fish in your pic is almost certainly marginatus based on the shape of the head.

**Czyne** · 31st Mar 2009, 09:35

barmby, the rounder bit seems not to be 100% but it does help to determine which one it most likely is. There are exceptions to both, but in general I think you're right that marginatus are plumper than their counterparts. Length really is the best indicator, but for the short-term, I guess speculation on which traits are most common in each will have to do as a process of elimination.

Matt, I'm not sure what you mean regarding the head shape, but I do agree that it's most likely marginatus. What's the difference between the two with head shape?

One thing my fiance also noticed is that marginatus tends to get a black stripe on the anal and sometimes dorsal fin; whereas trifasciatus usually has no black marking on either. When they do, it's more of a streak than a well-defined stripe. Colors really aren't a very good indicator, as CK said earlier, but pattern markings often are.

**barmby** · 31st Mar 2009, 09:49

We are slightly more lucky in Singapore. Because the marginatus will look out of place when placed in a same tank or right beside a tank of trifasciatus. Therefore, it is quite distinct

**Czyne** · 31st Mar 2009, 10:04

You guys seem to get really awesome livestock there, for both quality and selection. In my city (well, one city over... this city has next to nothing

), we have only what I'm guessing is marginatus, plus beckfordi and eques all in the same tank. The owner could only name the beckfordi when asked what kinds they all were, but he didn't know which one it was of the 3. No other shops even carry nannostomus, so I'm thankful to just have access to them.
The beckfordi and 'marginatus' are about the same size as eachother right now, but the marginatus ARE mostly plumper than the other two kinds in the tank. They also show all of the traits more commonly found in marginatus than trifasciatus now that I have a better idea of what to look for, so I'll be picking up more of them soon.

**barmby** · 31st Mar 2009, 16:33

Indeed, Singapore fishkeeper is very lucky. But N. trifasciatus and N. marginatus is seasonal. They will appear during certain months whereas Beckfordi appears all year round. Beckfordi does not seem to be very popular because they are not exotic compared to their cousins. Nannostomus espei will be great to have. But we are going to pay premium for this pretty fish. Cheers

**Matt Ford** · 2nd Apr 2009, 03:00

Originally Posted by Czyne

Matt, I'm not sure what you mean regarding the head shape, but I do agree that it's most likely marginatus. What's the difference between the two with head shape?

If you check CK's excellent pics closely the difference is quite clear. The trifasciatus has a proportionately longer snout and is an overall slimmer-looking fish.