Properly planning a large water tank in the basement

I hope I can post this here since people might be more knowledgeable about insulation and mold etc.

I am planning a large water tank (4.8m x 2.2m) in the basement for animal husbandry.
The entire tank is made of fiberglass (GFK) and rests against 3 concrete exterior walls.
The tank is 1m high and the room height is 2.5m.

The water will be at a temperature of about 25-27 °C.
The air temperature will be around 27-35 °C.
So everything will be very tropical and humid... humidity about 80-90%.

Now to my problem.

I want to protect the 3 concrete exterior walls that are adjacent to the tank from moisture and mold.
And for that, I want to insulate the whole thing a bit so I don’t waste too much energy heating the tank.

I was thinking of the following wall structure:
For the exterior wall at the tank height up to 1m finished floor level (exterior wall, Lastogum coating, 20cm Styrofoam, fiberglass tank)
For the exterior wall above the tank from 1m finished floor level (exterior wall, Lastogum coating, Wegiplatte, Lastogum coating, tiles)

Now I am just wondering if that is enough? Or too much? Keywords dew point shift, mold growth in the wall?
Vapor barrier?