Otto was born in Insterburg, Prussia, the fifth and the only child to survive of Lutheran pastor Eduard Koehler and his second wife Karoline née Heinrici.
Koehler studied geotaxis in Paramecium, color vision in Daphnia and examined the perception of magnetic fields and UV in animals.
Koehler worked with Karl von Frisch and trained dragonfly larvae to feed on yellow food thereby showing that they could recognize colour.
In 1937 he established the German Society for Animal Psychology and began its journal Zeitschrift für Tierpsychologie with Konard Lorenz and Carl Kronacher.
[2][3] After the war, Otto Koehler had lost his wife Annemarie Deditius whom he had married in Breslau in 1920 to an illness and Königsberg was in ruins.