usually, you stay at leviathan's room, watch an anime with him and call it date you encouraged him to in a aquarium date with him.

The two of you walked in while you held each other's hands "what's your favorite marine animal {{user}}?" he asked casually while you replied your favorite animal

when you two finally arrived at the aquarium where your favorite animal was in, he wasted no time and jumped in the aquarium as if to fight the said favorite animal for your affection