Looking for sub tropical species?

[Lollum96]

Looking for some new species that I can explore for stocking my upcoming tanks. Ideally they need to be sub tropical!

I have a lot of interest in medium to large sized aggressive and predatory species. But honestly interested in anything cool or unique.

When I say subtropical it's unlikely to drop below 18 degrees Celsius but the lower they can withstand the better!

At 39p per kw for electricity it's just not economical to heat the majority of my tanks. My bill is already nearly £300 a month.

Sub tropical species that I currently have are a
Salminus brasiliensis (golden dorado) and a Channa ornatipinnis (Burmese Spotted Snakehead).

Appreciate any recommendations!!

 

[duanes]

Any species from Uruguay or Argentina would fit that bill.
I have kept a number from that area, and they have taken water temps down to 50'F (10'C) without a problem.
Some pics

Australoheros sp red ceibal (left) Gymnogeophagus Rio Yerbalito (middle , and Gymnogeophagus sp Paso Pache right

Cichlasoma dimurus "Bella Union" above
There are also a number of Crenicichla pike cichlids from that area, Crenichcla saxatillus "Uruguayan variant", below

 

[Lollum96]

Any species from Uruguay or Argentina would fit that bill.
I have kept a number from that area, and they have taken water temps down to 50'F (10'C) without a problem.
Some pics
View attachment 1521539View attachment 1521540View attachment 1521541
Australoheros sp red ceibal (left) Gymnogeophagus Rio Yerbalito (middle , and Gymnogeophagus sp Paso Pache right
View attachment 1521542
Cichlasoma dimurus "Bella Union" above
There are also a number of Crenicichla pike cichlids from that area, Crenichcla saxatillus "Uruguayan variant", below
View attachment 1521543

Thanks for the response!! I really like the Australoheros sp red ceibal and I've found an established pair of them locally!

When you say any species from Argentina are you literally meaning any species from that area?

Based on this list here

Freshwater fish of Argentina

Freshwater fish of Argentina.

tropicalfreshwaterfish.com

I could keep Oscar's (Astronotus ocellatus), Black Acara (Cichlasoma bimaculatum) and even the Red Bellied Piranha (Pygocentrus nattereri) all as subtropical species without a heater?

But when I search these fish species in Google all the care sheets list them as tropical 22 degrees c to 30..

If you could drop me some further information on this would be massively appreciated!!

 

[duanes]

If you can establish that the source of those variants, have ancestors that were captured in Argentina or Uruguay are the ones you are getting, they should be adaptable to the cooler temps.
But an oscar from say central or northern Brazil , or an Amazonian red belly Piranha would probably not have the same tolerence those from southern South America possess.
The variants that have adapted to temperate countries have done so over millennia, and although they may be the exact same (or similar) species, have been hardened by survival of the fittest cool water gauntlet.

It's the same in the US, there are gars that survive winters in Wisconsin and Minnesota, but transfer a florida gar to one of those states, and it would probably be toast.

 

[Lollum96]

If you can establish that the source of those variants, have ancestors that were captured in Argentina or Uruguay are the ones you are getting, they should be adaptable to the cooler temps.
But an oscar from say central or northern Brazil , or an Amazonian red belly Piranha would probably not have the same tolerence those from southern South America possess.
The variants that have adapted to temperate countries have done so over millennia, and although they may be the exact same (or similar) species, have been hardened by survival of the fittest cool water gauntlet.

It's the same in the US, there are gars that survive winters in Wisconsin and Minnesota, but transfer a florida gar to one of those states, and it would probably be toast.

Thanks for the advice! But honestly I feel that it would be near impossible to source these fish species and establish the ancestors of them..

Do you know how I can find any advice or lists on what species I can buy that can withstand sub tropical temperatures?

Rather than trying to source species which have temperature tolerant genes.. Because here in the UK most suppliers simply don't have them details to hand.. I actually tried with a few of my common places for sourcing rare species in the UK.

Just out of interest. If I was to put an oscar in a tank at 25c and reduce the temperature by 2 degrees every few weeks down to 16-18 Celsius do you not think the chances are high that they would adapt to it?

 

[jjohnwm]

18C is not that cold; the average temperature is less of a concern than the lowest you can reasonably expect. If you regularly get a week or two at 10C...plan on 10C. Likely any North American species of gar would fit the bill, as would bowfin. Apparently at least some species of Goonch like cool water also, not sure exactly how cool they go. American Eels are pretty secretive but still have that weird "eel-vibe" going for them.

Lots of those Uruguayan cichlids would be great; I have Gymnogeophagus rhabdotus and Cichlasoma dimerus outside right now, and they...along with the G.balzanii I kept previously...easily tolerate low 50'sF temps.

Sturgeon...Highfin Sharks...many of the livebearers, including not only common Swordtails and Mollies but also many of the interesting Goodeid livebearers...apparently American sunfish species are becoming popular in Europe? There are lots of temperate-zone fishes that would be perfect, it's getting them that is the trick.

You could work the Oscar down towards that temperature without killing it outright...but I think that it would be stressed, weakened and prone to any number of other health problems. Sorry, but you are not going to force a fish to evolve to suit your tastes.

Don't forget the famous experiment done by Mark Twain. He reduced the amount of food that he provided to a horse a little at a time, with the goal of producing an animal that could subsist on no food at all. The experiment was a complete success until he got down to a handful of feed per day...at which point the horse died.