True Freshwater Eels?

[HexHammer]

Here's his evidence for the G. polyuranodon being a freshwater eel.

The only record of an elver of this species was, however, found in an estuary at a salinity of 33·4.

http://fishprofiles.com/profiles/marine/OthersFW/Gymnothorax_polyuranodon/

This eel seems to do equally well in freshwater, brackish water, and pure saltwater.

Despite the name "Freshwater Moray", this eel is actually a brackish water fish

 

[masone]

Putting a fishprofiles page against a peer reviewed journal article is hardly proof. Especially when it contains obvious errors (they don't occur in lakes, they grow bigger than 90cm, hell the pic isn't even right). Here's what I know as someone who lives in the area where these eels are found, observed and caught them in the wild and has visited and talked to the scientists working on them and seen them in their aquariums. They occur in the same creek and river environments as other catadromous "freshwater" fish such as Lates calcarifer, Kuhlia rupestris, K. marginata, Anguilla reinhardtii, Stiphodon sp., Giurus margaritacea etc. While it is highly likely that they are catadromous, they are fully capable of living as adults in full fresh without the need for the addition of salt. For all intents and purposes this makes them a freshwater fish as far as hobbyists are concerned unless they are interested in attempting breeding them. As I have previously said, the next step in the research is otolith banding to see how much time, if any, is spent in brackish or marine environments and at which stage of the life cycle as well as tagging and tracking adults in their creeks. Until that research is finished and published...

 

[HexHammer]

Here's his evidence for the G. polyuranodon being a freshwater eel.

If you read carefully you would see that the elvers only are found outside of freshwater, therefore it isn't a true freshwater fish, just like most other eels, who can live their entire life in freshwater but migrate to brackish/salt to spawn, then goes back to freshwater.

 

[aussiemonsters]

One single elver
How is ANY catadromous, amphidromous or diadromous fish that lives in freshwater NOT a freshwater fish
"then goes back to freshwater"

 

[HexHammer]

One single elver
How is ANY catadromous, amphidromous or diadromous fish that lives in freshwater NOT a freshwater fish
"then goes back to freshwater"

The topic of this thread is "true" freshwater, suggesting that they can live "naturally" their whole life in freshwater, but fact is that eels will migrate to salt or brackish waters to spawn.

 

[Chub_by]

The topic of this thread is "true" freshwater, suggesting that they can live "naturally" their whole life in freshwater, but fact is that eels will migrate to salt or brackish waters to spawn.

Fact is they only spawn there, and I know of eels which have been kept in aquariums for over 25 years

 

[aussiemonsters]

Every thread needs a pic. Off species but not off topic, this one has been in freshwater for over 40 years (and by the way pretty sure she wont be coming back when she does finally decide to make the journey to spawn)