Fish ID

[duanes]

This individual was caught in a stream by a friend, on the island where I live, 10 miles off the southern coast of Panama.
It is about 4" long, hardly ever strays from lower than the first couple inches of the surface. and it has 2 dorsal fins.



It is always in constant motion.
It could have found its way to the island, as an escapee from the bilge of a ship passing thru the Panama canal, or could have been washed onto the fresh water stream at high tide.

 

[FJB]

I don't know, but -
With two dorsal fins, the only thing that comes to mind is Atheriniformes. The shape and behaviour would be consistent with something like that. There are some genera and species in North America (Menidia, for instance), but I don't know of any in Central America. Most are of course in Australasia. But I can't come up with another with clearly two dorsals, and certainly no adipose fin. Interesting find!

 

[The Masked Shadow]

Im here with the soda and popcorn

 

[kno4te]

Think it’s agonostomus monicola.

 

[FJB]

I agree it can also be a Mugilidae, thus Agonostomus is a very good possibility. I did not think of Mugilids when I suggested Atheriniformes. Not many possibilities for sure.

 

[duanes]

Think it’s agonostomus monicola.

Good eye.
I googled it, and found the Mountain Mullet in my field guide to the fishes of Costa Rica, it ranges from Baja California to Colombia, and the images in both places confirm your ID.
Stating it is a rheophillic species (the streams on the island can regularly become raging rapids, its tendancy to hang out in the highest current of the tank its in, suggests that.
It is also known to stray far out to sea, which would account for it showing up on an island this far in the Pacific.
It will be interesting to see how, or if it survives in my newly setup 125.
Below, the stream it was caught in during the rainy season, here on Taboga.

 

[duanes]

Couple extra shots, it seems more comfortable in the tank, today, so its easier to shoot.

One of the things that distinguish it from others, is the the forward dorsal is just basically a set of spines.

I went looking for a few more in the stream today, its obviously a schooling/shoaling species, but no luck yet.
Being wild I wondered whether it would accept prepared foods, and it easily took to crushed pellets.

 

[Toiletcar]

Cool find Duane ?

 

[Fishnerd360]

Cool fish, looks like it’s a good jumper with the angle on the pectoral fins.

 

[Deadeye]

Very nice fish! Looking forward to seeing if you can get some more. Seems like something I’d love to get, but will never pop up at the lfs.