The subspecies is native to northwestern and western Madagascar and typically inhabits trees.

[3] Koch's giant day gecko is often treated as its own species, Phelsuma kochi Mertens, 1954.

[citation needed] P. m. kochi is widely distributed in northwestern and western Madagascar on the coast and in the inland.

[citation needed] Koch's giant day gecko feeds on various insects and other invertebrates.

[citation needed] P. m. kochi should be housed in pairs although successful group breeding with one male and several females has been reported.

In captivity, these animals can be fed with crickets, wax moths, fruit flies, mealworms, and houseflies.