The biggest problem I had with small enclosures outside in the US, were wild temp fluctuations.
Even in 100-300 gallo rubbermaid stock tanks, water temps in the early morning might be as low as 60'F but in the late afternoon on sunny days might heat up to 80'F. I suppose this might depend on where you are located.
Some cichlids from temperate zones like Uruguay or northern Mexico could handle the flip flop, while other Central American cichlids from more stable areas couldn't.
I had Herichthys pearsei and some Vieja die on cool nights, while Geophagus braziliiensus , Australoheros, or Herichthys carpintus did fine.
I ended up solving the wild swings by using my 1500 gal of ponds as a sump, because in ground, they had more stable water temps.
Below Australoheros red ceibal spawned in an outdoor 50 gal tank, while using the large ponds stabile water temps to mitigate the swings.
The sunlight was great at providing algae for rapid fry growth, but could also overheat the tank by 3pm.
Below the same tank using the more stable temp pond as a sump
