The problem here is you’ve got a small dungeon, so your pretty limited on what can reasonably go in it. Also, depending on your scale, the three secondary rooms are too close together. If there’s an encounter in any of them, it’s likely to draw every other encounter.

I’d suggest staggering the entrances, or maybe adding curves between them. Alternately, this could be a lair for 3-5 larger creatures, and each room is part of their life in some way. Maybe something amphibious that needs to breed in water.