Here is the honest part first: Leo needs to be seen, and Pisces often struggles to say clearly what it sees. Leo will tell a room-filling story about the promotion, the party, the thing they made, and want Pisces to meet that energy with matching enthusiasm. Pisces, more likely to feel their way through a response than perform one, might just get quiet and soft-eyed, which Leo can read as disinterest when it is actually the opposite. That gap between a sign that broadcasts and a sign that absorbs causes real friction, especially early on, when Leo starts wondering if Pisces even noticed the new haircut, and Pisces feels hurt that their quieter form of devotion, the remembered detail, the anticipated need, does not seem to register as love at all.
But once they learn each other's language, this pairing has real tenderness in it. Pisces is ruled by Neptune, dissolving and dreamy, and there is something in that dissolving quality that Leo, so used to holding a firm shape in the world, finds genuinely restful. Pisces sees past the performance to whatever is underneath it, and Leo, who rarely gets looked at that closely, can end up more moved by that than by applause. In return, Leo's warmth gives Pisces something to swim toward, a fixed point of gold that makes the formless feelings feel welcome rather than embarrassing.
The friction point worth naming honestly: Leo's fixed nature wants stated plans, dinner reservations, clear declarations, while Pisces' mutable drift resists pinning down. Leo will ask "so are we doing this or not" and Pisces will need to feel their way there instead. Patience with that difference, on both sides, is what makes this one last.