Surfing Waves

My family and I are all pretty new to surfing. We are 6 months in on a year in Central America. My son (12, 35kg) has done well to learn on a Round-Nose Fish 5’6”, 29L. He is comfortable taking off in 3-4ft waves but can’t duck dive (board too floaty) and seems to struggle to make it turn (skill or width or both?). I wonder if the width and volume are now holding him back from learning? In one way I think he could benefit from a smaller board but on the other hand, there is probably lots of improvement still to be made with this one. Any thoughts from others with kids who have watched their skills evolve? One option might be to just find a small cheap beater and let him have at it. Advice appreciated! Thx.

Yeah fish boards seem to be more difficult to turn if you lack the skills so it could be that. The wide tails make the board go faster but slow down the turning. Foot positioning is more critical on wide tailed boards. The not being able to duck dive isn't such a bad thing because it forces you to learn other skills like how to avoid needing to duck dive which are more important than learning to duck dive. There are others who can give you recommendations for boards.