Yeah it may be too warm for those newts.
I have 3x 4' 6500k tubes including one plant tube over them atm.
The 3 options for fish which I may include are: leopard danio, short fin Betta, or Khuli.
They all do ok in 4" of water and plants.
However my cherry barbs fry are growing, I may include them and not have to buy any fish.