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i found this fish at the lfs today and the shop owner called it a "monarch" fish, but he also had a thick korean accent so he could have said something else and i just misunderstood. anyway, i am having a very difficult time identifying it, but so far it seems to like its new home

this is the best pic i got of it while it was sitting in the bag waiting to go into the tank. i thought it might be some kind of barb, but i'm not finding any barbs that are even close to it in markings. it's definitely a freshwater fish though, as it was in a tank with a couple gouramis and some small small tetras.

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"That's the trouble with political jokes in this country... they get elected!" -- Dave Lippman

Actually, that's a brackish water mono fish.

Monodactylus argentus or sebae

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i see. no wonder i couldn't find any freshwater identification on it. how long do you think this fish could last in a freshwater tank, being that i don't have a brackish setup and don't have the room to start one?

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"That's the trouble with political jokes in this country... they get elected!" -- Dave Lippman

I don't know, but unless you have cories or other fish that can't handle salt, it couldn't hurt to add a little bit to the tank for the time being.

I've narrowed it down to Monodactylus argentus, though, which reaches a bit over 10 inches SL (27 cm).

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I've never seen a 10" mono, but there's a mono that I've seen live for quite a long time (over a year if not a couple years) in freshwater with no apparent decline in health. Your specimen is a little on the skinny side, but I'm sure that'll change with a little bit of care.

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The aquarist is one who must learn the ways of the biologist, the chemist, and the veterinarian.

That was a number I got off Fishbase.org, so it probably applies to wild specimens.

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yea its a mono and i have seen a 10 inch before in a 400 gallon tank full salt........... they go trew stages they can start in freshwater then go to brackish but to be happy they will need a full on saltwater tank and they are schooling fish.....

yeah, since you helped me identify it, i'm pretty sure it's argentus as well. it just fits. well, the lfs has a "no return" policy so i guess we'll see how long i can keep it happy in a non-brackish, non-salt environment. i've read on another site that they can live in freshwater with high alkalinity, hopefully that's true.

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"That's the trouble with political jokes in this country... they get elected!" -- Dave Lippman

Is there no other LFS that will take it?
I think its shocking that stores have a no return policy. Should find out what the fish are to be fair, though. But ya, i'd try and pawn it off somewhere else

Definitely Monodactylus argenteus. It's the only one of the two species that develops bright yellow markings along the dorsal fin. Also, Mondoactylus sebae is taller, and has two full length body stripes.

Here's some images for comparison ... first, Monodactylus argenteus]http://www.aqua-fish.net/imgs/fish2/finger-fish-profile.jpg[/link], and second, [link=Monodactulys sebae. (Click on links to view pics).

Incidentally, Monodactylus sebae was successfully spawned in the aquarium back as far as 1977 (I have a feature in a back number of TFH about this). Can't recall if the same has happened with argenteus though.

Basically, both species are shoaling fishes, the more the merrier, though they can be nippy and territorial once adult, and consequently need LOTS of space as they grow, not least because they're also fairly active fishes. They can also be fin nippers (argenteus can be especially troublesome in this regard, and consequently, one should never keep this species with Angel Fishes or Bettas), but oddly enough, can also exhibit a fair amount of shyness in the aquarium even if conditions are to their liking. This is usually overcome by making sure that they have reasonably active top swimming companions, as they seem to regard the presence of top swimming fishes as a sign that there's no "danger from above" in the form or fish eating birds etc.

If you have to keep this fish in freshwater until you can set up a decent brackish aquarium for it, then make sure the water is hard and alkaline - the sort of parameters that suit Rift Lake Cichlids will be the parameters you're looking at.

Good companions will be larger Rainbow Fishes, Scats, Archer Fishes and some of the medium sized Gobies that like brackish conditions. Alternatively, if you know a marine aquarist looking for something different, because the fish is euryhaline, it can be migrated to fully marine water with time and care, and sometimes displays more vibrant colours in a marine setup. Make sure that any transitioning from fresh or mildly brackish through to fully marine is performed over several weeks if attempting this though.


Panda Catfish fan and keeper/breeder since Christmas 2002

also, just looked again and noticed it is rather pinched, too.

Best remedy for that is a week spent fattening it up with live foods. Toss in a mix of live Bloodworm, Brine Shrimp and Daphnia with it for a week, and it'll soon start to develop a nice healthy fullness.

Also, it'll be happier if it has a small group of its own species, provided there's sufficient space to allow the fishes to adopt areas of the tank as their own once they start exhibiting some territorial behaviour. Monos are odd like that - they're simultaneously shoaling fishes AND territorial.

Panda Catfish fan and keeper/breeder since Christmas 2002