The katakana syllable ティ (ti). Its equivalent in hiragana is てぃ (ti).

an African wildcat

courage; nerve (as of steel)

源五郎鮒: Carassius cuvieri the Japanese crucian carp or white crucian carp, a type of 鮒 (funa, “crucian carp”), an edible freshwater ray-finned fish related to carp and goldfish and endemic to Lake Biwa in Japan