Compatible fishes?

[Aqua 4k]

Hi A Aqua 4k
Min 19C, but for how long/often? What's the average & max?
Is the 19C here & there storm-occasional, or constant Nov~Feb?

This is an outdoor system? Pond?
If occasional overnight drop, you might be able to get away with a lot via depth/volume, cover and/or a heater.
If a 100gal tank on the balcony, a horse-blanket might help, or make a cover-box out of 1" styrofoam board (what fridges are shipped in) & keep an eye on the weather forecast.

Re. stock: I would absolutely suggest American eel - bright & interactive & bucketloads of personality. Strong, active, ravenous & decor-destructive, too...

Thank you!

It's and indoor tank but I have a heater and a fan and i control the temperature between those rangs.
The american eel it's cool.
The tank have two water pumps 1000 l / h each one.The fluval fx4 and a nicrew oxygenator.
Have a lot of caves and rocks.
I will try to put a photo of the tank, so you can see it

 

[Andyroo]

So room-temperature, 19~22C depending on drafts

That's a good volume, but your aerator putting room-air through the tank facilitating temp.fluctuation with the room. You may be able to reduce fluctuation just by turning the bubbles off at night or when you're out (and the heating's off), though I don't think that's much of a flux so long as your stock is all temperate & Ok with that temperature (like goldfish). A rain will drop a smaller river by a fair few C.
Where are you, though? I ask as eel will be there & some gobies & crayfish & even some newts, but the Americans get the really (REALLY) colourful & nifty stuff at that temp.range: darters, dace etc. Do check loaches, including the big long ones out of Chinese/Laotian mountain streams. How about Axolotl?

 

[Aqua 4k]

So room-temperature, 19~22C depending on drafts

That's a good volume, but your aerator putting room-air through the tank facilitating temp.fluctuation with the room. You may be able to reduce fluctuation just by turning the bubbles off at night or when you're out (and the heating's off), though I don't think that's much of a flux so long as your stock is all temperate & Ok with that temperature (like goldfish). A rain will drop a smaller river by a fair few C.
Where are you, though? I ask as eel will be there & some gobies & crayfish & even some newts, but the Americans get the really (REALLY) colourful & nifty stuff at that temp.range: darters, dace etc. Do check loaches, including the big long ones out of Chinese/Laotian mountain streams. How about Axolotl?

Thank you!
Im from Spain.
In the tank i have goldfish.,and i want to put some variety of fish.
For the moment i saw this ones:
Lima shovelnose
Rope fish
American eel
Delhezi bichir
Platisilurus mucosus
Mystus boucorti
Pimelodus blochii
Loricaria similimma
Rineloricaria heteroptera
Pseudohemiodon apithanos
Giant bumblebee catfish
Apollo shark
Siren lacertina(similar to the axolotl)
brachirus panoides(false sole)

You think they can be okay with the goldfish?,not all of this fishes I will select only a few.
If you have any other suggested fish...
It's so difficult to find fish(big ones) that can do well at low temperatures,at small fish there are a lot but i want the biggest one.Cause i have in my other tanks small fish and this 100 gallon is my biggest tank and i want big fish.
When i arrive to my home i will put a video of my tank.
The video it's going to be on youtube so if you enter on my "channel" you will se my other two aquariums

 

[Andyroo]

For that list you'll need to give your golides away & get a heater. For many of them, you'll want to upgrade or add a bigger tank, too.
There you go: a bigger with heater & move the goldy-100 to the verandah.

I suggest one try not to overstock: strive for happy fish with lots of ecological redundancy with swimming-space & water volume & filtration & ecosystem rather than just a broad collection. Overstocking and/or cramping leads to heartbreak.

You like your goldfish, what's wrong with sticking to goldfish & maybe a (European) eel with two or five crayfish? I've seen comets at >20cm, which would be about max-size for your 100gal. as they like to be active, a little flow even. Easier still, a half-dozen weather/dojo loaches & those same crays?

 

[Rocksor]

Planetcatfish.com will have the temperature ranges for the catfish you want. This includes pleco types. But, because some of the catfish have feelers, you need a tank width twice as long as the catfish with the feelers extended out for their general health. A 100g tank limits you to catfish with feelers to no longer than 8" in total lenghth.

Another issue is the lower temperature range that you want 19C. You will have to stock low, or maybe moderately if you can do lots of water changes (more than once a week). The reason being is that the bacteria to process ammonia and nitrites doesn't work as well at lower temperatures.

 

[1 2many]

get a heater. For many of them, you'll want to upgrade or add a bigger tank,

+1

 

[Ashtons Fishroom]

well white cloud minnows are a perfect match!

 

[Aqua 4k]

Hello thank you for all!
I have two heaters and a fan.
And I want to put a minimum of 19 celsius and then a maximum of 24 celsius.
The rest It is going to be the ambiental temperature normally at winter like 20-23 celsius,at the noon 24 celsius and at night 19 celsius.
I don't wont to overstock the aquarium cause I now It can be a disaster.
Cause the temperature it's going to be a little bit lower and the bacteria don't proceso fast i want to put natural filtration too.
Now i hace White cloud minnows but i am going to put them into a 27 gallon tank.
Cause when the goldfish grow to their maximum size the White cloud minnows can be eaten.Not normally but can happen.
I am going to think cause I need,but for the moment I think I will do your recommendations
Thank you again for all the info

 

[Deadeye]

I’d look into various coldwater bottom dwellers or coldwater cyprinids.
Goldies don’t really do well with many other fish IME because they are just too placid and those fins cannot be resisted.

 

[Magnus_Bane]

well white cloud minnows are a perfect match!

They'll just end up being snacks for the goldfish. Just because they aren't normally predatory doesn't mean that it will pass up some free protein. Just like how there is plenty of videos out there of deer and cattle eating baby birds, just because it's an herbivore doesn't mean that it doesn't appreciate a nice meaty meal every now and then.