Flounder Id

[Synirr]

I just moved to Austin, TX, and found a great fish shop. It really cators to hobbyists, and carries a lot of harder-to-find fish and wild-type cichlids. Anyway, they had this little flounder that I was assured was freshwater, and they do have a brackish tank set up it could have been in, so I thought I'd take my chances and get it since the shop was so good overall. I definitely want to make sure on the ID though, obviously I don't want to continue housing it in freshwater if it is not
Here are some pics of the little fella, any input would be appreciated:

Underside

 

[nmonks]

Difficult to be sure. It's definitely one of the Achiridae, the American soles, rather than one of the Soleidae, the true soles. The big paddle-like tail is the giveaway. If you look at this page, you can see pictures of the different species and have a stab at identifying it yourself. A couple of Japanese web sites with good photographs (and the names in English) are:

http/www.geocities.co.jp/AnimalPark-Shir...kareiindex.html
http/ww8.tiki.ne.jp/~yashu/page004.html

It is almost certainly one of two species: Trinectes maculatus (a.k.a. common hogchoker) or Catathyridium jenysii (a.k.a Achirus errans).

It does look fairly like Catathyridium jenysii, a true freshwater species, but that species is quite rare in the trade. Common hogchokers are far more common.

A "safe" approach is to keep the fish at 1.005 SG. That will be harmless to freshwater species, but therapeutic to brackish water ones. I'd be tempted to do that until able to identify the fish. Certainly, a sole should be kept alone for a few weeks. They can be tricky to get feeding. Don't foget that they're nocturnal. I have some basic notes on these fish generally here.

Cheers,

Neale

 

[Synirr]

Thanks for the links! I'll have to net it tomorrow and check it out, it has been burried under the sand. I did see it eat a brine shrimp today, so I think we're ok on the feeding. The shop it came from does have a number of rare and hard to find fish in the hobby, so it's definitely possible it could be Catathyridium jenysii, but like I said, I'd like to make sure.

 

[Loko17]

Cool find, fish and store. Flounders are very cool, I wonder how big it'll get.