# Freshwater Flounder



## frozenoak (Jul 30, 2005)

I was at the LFS today looking at fish and I got a couple freshwater flounder. Problem is, I don't know jack about them. 

For starters, I am wondering if they are really freshwater or not? (my hunch is they are brackish at best) Second, what do they eat? Third, how big do they get? Forth, does anybody know anything at all about freshwater flounder?

I hope I haven't just purchased a headache but they looked so cool. I will have pics when the green water gets clear again.

Thank for the help,
dale


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## neonfish3 (Feb 12, 2004)

Does it look like this:
Hillstream loach
http://www.aquariacentral.com/articles/hillstream.shtml

Steve


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## plantbrain (Jan 23, 2004)

There are FW flouders that come from extremely soft FW. We caught many last year at the plant fest in FL in a soft blackwater river.

They like worms and have a very good jumping ability also.

Regards, 
Tom Barr


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## JimM (Aug 26, 2005)

http://www.aqualandpetsplus.com/Oddball, Flounder.htm
HTH


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## ranmasatome (Aug 5, 2005)

yummy..


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## Veneer (Jun 12, 2005)

The "freshwater flounders" most typically available in the U.S. hobby are native _Achirus_ spp.; at least lightly brackish salinity and cooler temperatures are vital to long-term survival. True FW species are occasionally imported from South America, Africa, South Asia, and Austronesia.


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## plantbrain (Jan 23, 2004)

The native species in FL I caught had zero salinity and were 70 miles from the salt water. I would challenge that this species requires any salt for breeding, survival or general health. They are present year round in Rio ***** *type* blackwater(GH/KH near zero, pH, 5.0-5.9), I've caught fry(1/2") and adults(2-4") in Central FL for a couple of years at the same locations, indicating they breed there. The same location also had true FW pipefish, the only true FW pipefish known.

Perhaps other species prefer brackish waters..........but at least one does not. Coolers temps, most of the waters were 72-73F at the location, the fish I kept at home had a temp of 82F.

Regards, 
Tom Barr


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## frozenoak (Jul 30, 2005)

I feel so sorry for them.  I have so many plants that they can't get to the gravel to lay flat. They mostly droop over the plant stems or cling to the wall. I may have to make my 10 gal QT tank into a brackish tank. That way I can also have the figure eight puffer I want.  Are there many plants that will do OK in brackish water? It would be a low light tank without adding CO2.


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## plantbrain (Jan 23, 2004)

Vals, Hornwort, Potamogetons, Hydrilla(forget using this one) do well in fairly high salinities.

The indian dwarf puffers do well in Planted tanks, SA puffers are also very much like the Fig 8's, and they are native to the soft FW. Fine sand, lots of current, lots of worms make flouders happy.

Regards, 
Tom Barr


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## frozenoak (Jul 30, 2005)

Thanks Tom.

I have been looking for an indian dwarf puffer also. The LFS had one a little while back but they sold it. They have about 30 fig 8's however. I would like to get a couple of the fig 8's but I know that while they may be able to survive FW they are a brackish fish. I think I may make my 10 into a brackish tank. If you know someone that wants to sell a dwarf please let me know.

I'm not familiar with the SA puffer. Do you have a scientific name for them so I can look them up?

Thanks again,
dale


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## Veneer (Jun 12, 2005)

plantbrain said:


> The native species in FL I caught had zero salinity and were 70 miles from the salt water. I would challenge that this species requires any salt for breeding, survival or general health. They are present year round in Rio ***** *type* blackwater(GH/KH near zero, pH, 5.0-5.9), I've caught fry(1/2") and adults(2-4") in Central FL for a couple of years at the same locations, indicating they breed there. The same location also had true FW pipefish, the only true FW pipefish known.
> 
> Perhaps other species prefer brackish waters..........but at least one does not. Coolers temps, most of the waters were 72-73F at the location, the fish I kept at home had a temp of 82F.


Note my wording. I do not dispute that regional variants of certain _Achirus_ sp. may inhabit full FW all their lives, nor that _Achirus_ spp. are characterized by strong osmoregulatory capacity - hence, tolerance of broad variation in salinity - (with juvenile specimens in particular notable for ascending rivers for significant segments of their lives). However, I would consider such species-breadth extrapolation of salinity preference from a secondarily landlocked population perilous. The occurrence of the otherwise brackish-to-marine organisms you mentioned in a freshwater milieu is (as with the Atlantic stingray, _Dasyatis sabina_, of the St. John's River) a likely relict of Late Pleistocene upheaval:



> Another theory, which is more likely, is based on the geologic history of the St. Johns River and the salinity tolerance of the Atlantic stingray. The formation of the St. Johns River has occurred relatively recently. In the late Pleistocene (less than 100,000 years ago), when seawater levels were higher than they are today, the land mass from the east coast of Florida to the east coast of the St. Johns River was underwater. As sea levels gradually declined, the land mass became more exposed and is thought to have formed a brackish water lagoon (similar to the Indian River Lagoon). As the sea level continued to recede, the river became more isolated from the ocean (except for its mouth) and gradually became the freshwater system it is today


(http://www.ecofloridamag.com/archived/stingrays.htm)

Note also the essentially landlocked sharks (_Carcharhinus leucas_ - specimens of which have been also recovered 2,600 miles [4,200 kilometers] from the mouth of the Amazon River), sawfish (_Pristis_ sp.), and tarpon (_Megalops atlanticus_) of Lake Nicaragua.

Of _C. leucas_: "Yet tagging studies by Thorson and his co-workers has demonstrated that Bull Sharks can survive in Lake Nicaragua for prolonged periods, with records of four to six years for some individuals. Bull Sharks do not, however, appear to reproduce in Lake Nicaragua or other freshwater habitats. Instead, this species seems to return to brackish water for courtship, mating, and bearing young. Bull Shark pups may not be able to meet the high metabolic cost of osmoregulating in fresh water." (http://www.elasmo-research.org/education/topics/p_fw_rays.htm)

Nonetheless, it is on the basis of personal experience that I have been led to conclude that the _typical_ "freshwater" flounder (in truth, nothing more than a juvenile hogsucker) cannot survive indefinitely in a tropical FW setup.


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## Veneer (Jun 12, 2005)

Further research reveals that the FL founders in question may in not, in fact, be of the genus _Archirus_ (revised to _Trinectes_, by some accounts).

External Article: http://69.44.152.177/viewtopic.php?p=216176


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## shadow (Jan 21, 2005)

These guys are really kewl, if a little hard to keep in my experience. I remeber the first time is saw one it scared the hell out of me in the fish store cos i just rose from the gravel out of the corner of my eye, since then i've always had a soft spot for them. We have three confirmed species in australia the seem to prefer brackish water but apparently they breed in freshwater, and their diet is mostly small fish and other crustaceans. There not often seen in fish stores and usually 30-40 dollars around my way, and normally hard to see in your tank because they camoflague themselves so well and are more active in the dark but make and interesting addition to a tank if your water parameters are on the brackish side. They can get to about 15-20cms but i've never seen one that big about 5-6cms is the biggest i've seen.


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## AmberSunrise (Sep 14, 2010)

Well I just got one from my local petstore and asked the guy if it would be ok in the tank with my ghost shrimp and he said yes! Now after getting home and doing research I see that ghost shrimp are their favorite meal! UGH! 

Now I dont know if I should stick it in my 30 gal angel tank or my 10 gal commuity tank now. The 30 gal has a raphael catfish so they might not get along so well. 

I wont be going back to that petstore again.


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