If you're referring to flounders, Wes of rarefish is offering some from south america right now.
Keeping Your New Freshwater Flounder
Aqualand's inside info on Achirus lineatus
Flounder Factoids
Origin - USA
Temperature - 70-85F
Lighting - Needs no special lights
Attitude - Seemingly shy and retiring
Security - Blends into the substrate
Foods - Start on live worms or small fishes
Size - Six inch max -- long not across
Water - Prefers slightly brackish water
Breeding Comments - Prolific breeder in the wild
Common Name: Though often called freshwater flounders, these guys do better in brackish water. We've also heard them called puppy tongues down south. In some areas they call them hog chokers. Seems farmers feed these as trash fish to their hogs. Hogs have trouble swallowing them, thus the name. Actually, hogs have very little trouble swallowing anything.
Appeal: Like the other flounders, these weird little guys have both eyes on one side of their bodies. Their left eye migrates to the right side of their bodies. The left side becomes its whitish underbelly. They spend all their time lying on their underbellies.
Color: Freshwater flounders try to blend into whatever's on the bottom. They can control the size of their various pigment pores to change from dark to light in the greys and browns. Some develop spots to complete the camouflage.
Sort of a 'Sucker Fish.' Freshwater flounders frequently plaster their bodies to the glass sides of their aquaria. They suck on the sides so strongly you'll usually have difficulty netting them. Some you need to pry off the sides. Once in a plastic bag, you often need to slit the bag open to get them out. Flounders can really hold on to flat surfaces. But, unlike the plecostomids and other algae eaters, these guys ignore your algae. They want live meat.
Size: Few people grow freshwater flounders to any size because they keep them incorrectly. The largest we ever saw was three inches across. Flounders fare poorly in a regular community tank. Beginners give them the wrong kind of water and expect them to eat fish food. Most won?t eat flakes at first.
Habitat: Ten-gallon aquariums work fine as starter tanks. Flounders need more room as they grow. They also prefer a sand bottom. In the wild, flounders congregate on mud flats. Do not attempt this at home.
Brackish Water. Adult flounders spawn in the mouths of rivers (where rivers empty into the ocean). The extremely tiny fry migrate upstream. You usually find flounders on the market at the one to two-inch size ? well beyond the fry stage. They start wanting more salt in their water as they grow larger. Give them at least two teaspoons per gallon. Increase the amount of salt as your flounders increase in size.
Foods: If it's small and moves, freshwater flounders try to eat it. Live blackworms or small earthworms work well to start with. Add some feeder white clouds also. They'd probably also enjoy ghost shrimp as they grow. You can eventually convert them over to frozen brine shrimp and frozen bloodworms. Some eventually convert to eating flakes or sinking pellets. Most community fishes will eat all the flakes before the flounders start looking for them. Flounders have an eating advantage at night.
Provide Cover: If you keep flounders with bigger fishes, you may want to provide a cave or two. However, in a tank with small mosquitofish, the mosquitofish need the cover. Freshwater flounders can overpower the smaller fishes at night.
Tank Mates: Feel free to mix these guys with other medium-sized brackish water fishes African butterflies, dragon gobies, African ropefish (if your flounder's too big to swallow), mollies, and other livebearers (because they like salt also). Livebearers also provide additional live food periodically. Since bumblebee gobies and freshwater flounders share the same needs, feel free to mix them.
Last Words: You needn't worry too much about temp. Like other USA fishes, freshwater flounders adapt to a wide range of temps. Just keep it steady. Set your heater to take care of their tank mates. LA.
They are really cool to watch though and I miss mine.