NANFA-L-- Not the worlds smallest fish.

Michael Sandel (
Thu, 26 Jan 2006 17:53:28 -0800 (PST)

Y'all got me curious, looks like Associated Press forgot to do a literature search.

Trimmatom nanus lost the title of world's smallest vertebrate in 2004. Paedocypris progenetica is indeed not the world's smallest fish or vertebrate (sexually mature or otherwise)...-in-least until someone finds a giant Schindleria brevipinguis.

Here's what I found.
The largest recorded individual; standard length:

Trimmatom nanus {Marine Goby} 11.7 mm.(Winterbottom 1989)

Pandaka pygmaea {Freshwater Goby} I couldn't find max size, but the smallest mature male is 10.0 mm, so it doesn't matter. See below.

Schindleria brevipinguis {Marine Goby} 8.4 mm! (Watson and Walker 2004)

Paedocypris progenetica {New Freshwater Cyprinid} 10.5 mm. (Kottelat et al. 2005)

The smallest recorded sexually mature individual:
Trimmatom nanus was 7.6 mm (Winterbottom 1989).

Pandaka pygmaea 7.5 mm (female) and 10.0 mm (male) (Miller 1984 as quoted in Thacker and Grier 2003)

Schindleria brevipinguis {Saltwater Goby} 6.5 mm! (Watson and Walker 2004)

Paedocypris progenetica was 7.9 mm (Kottelat et al. 2005)

All of these fishes except Pandaka appear to be heterochronic paedomorphs (development and growth stop once the sex organs mature, which may be earlier than the rest of the body). This means that Pandaka is a "developed" looking 10.0 mm fish. I haven't seen one, but I can imagine it looks cooler than the "larvalesque" Schindleria.

Another thing to think about is temperature. I read in one of the articles that higher temperatures speed up paedomorphism. Under experimental conditions, maybe someone can breed 4-5 mm individuals!

The world's smallest vertebrate was described by Watson and Walker in
Records of the Australian Museum. 2004. Vol. 56:139-141 ISSN 0067-1975.

Peace out
Mike Sandel
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