Southamerican fish for unfiltered aquarium

[Arkis]

Hello,

I am starting a (200 litres / 53 gallons). I want an Amazonian biotope but without active filtration. I have lots of plants, moss and active soil which should maintain the chemical cleaning in good levels. The aquarium has no heater and no filtration. The only accessory is LED light for plants.

What south american fish could be thriving in these conditions? The temperature is around 21°C (70°F) in winter and 26-28°C (79°F-81°F) in summer (during temp peaks). Right now there are only snails and Corydoras in the aquarium. 

I am not sure if I want for example one pair of some medium-big fish or a school of smaller fish. Both options are possible and I will choose only by the looks and needs of the fish. 

I was looking on some Akara blue fish but they are not really hardy (they are very much dependable on the quality of the water) and they need warmer water. 

Thank you for your suggestions. 

[MyFish]

On 1/28/2022 at 7:04 AM, Arkis said:

Hello,

I am starting a (200 litres / 53 gallons). I want an Amazonian biotope but without active filtration. I have lots of plants, moss and active soil which should maintain the chemical cleaning in good levels. The aquarium has no heater and no filtration. The only accessory is LED light for plants.

What south american fish could be thriving in these conditions? The temperature is around 21°C (70°F) in winter and 26-28°C (79°F-81°F) in summer (during temp peaks). Right now there are only snails and Corydoras in the aquarium. 

I am not sure if I want for example one pair of some medium-big fish or a school of smaller fish. Both options are possible and I will choose only by the looks and needs of the fish. 

I was looking on some Akara blue fish but they are not really hardy (they are very much dependable on the quality of the water) and they need warmer water. 

Thank you for your suggestions. 

Where did you get your info on Blue Accra?  Everything I’ve read says they ARE hardy.  
 

https://www.tankarium.com/electric-blue-acara/

I was thinking of getting a few for my tank since I gave Fluval stratum and can’t raise my ph above 6.8

[Arkis]

Even on the website you postel it says "Filtration/Flow Rate: Prefers well-filtered water with a strong flow rate". Acaras are very sensitive to nitrates and overall water quality. In unfiltered aquarium I can't get such nice levels like with a canister filter thus it would be really hard to keep them. Well, not with daily water changes but that's not what I want to do. Also the temp are lower than they would like to be in. 

[MyFish]

How about some South American tetras? 
Like black water living tetras May work well in your minimal/no flow  tank.  
 It’s going to be a little difficult without filtration.  Will you be having a sponge filter?  If so that will open up more choices because you won’t need to do water changes so often.

im curious to what you decide, I’ll search 👀 for some matches; can you post your parameters again, tank size, (w/dimensions L”xW”xH”) type of lighting, will you be using Co2, fertilizers?  Temperature?  
 

thanks.

[Goosedub]

You are going to want it lightly stocked. You could try apistogramma borellii. Your system seems doable, but I would think your goal would be to care for the fish the best possible. It seems by “hardy” you mean can take a beating, which I don’t think should be our goal from the start. Yoo ok I can care for any fish that can go down to 70 degrees in this setup as long as you keep an eye on your water parameters.