Outground concrete tank vs One meter deep mud pond

[FishDojo God]

It is getting cold now, around 21 c.

What would be best?

Let the Pbass in the concrete tank troughout the winter (around 15 c) and add a 200w electrical water heater (might be not enough).

or

Tansfer the fish to a one meter deep mud pond exposed to sunshine with water hyacinths and other aquatic vegetation,glass shrimps, gouramis, tilapias, frogs and snakes.

 

[channarox]

get more heaters?how cold does it get in the pond?
i personally would just get more heaters for the pbass sake and keep them in the tank.

 

[alcohologist]

you can look into using sunlight to heat the water, through black plastic.

 

[silverdragon]

id go for the 2nd option with direct sunlight heating..