Why is there so many mobs spawning in my new biome?

I made a Biome called "The Perpetual Ocean", With 5 Total Spawnables.

Tropical Fish, at 15 weight 1-1 min and max groups,

Pufferfish and Salmon at 10 weight 1-1 min and max groups,

and Turtles with 5 Weight and 1-1 min and max groups.

and my Custom Megalodon mob, with 1-1-1 Weight min and max grouping,

But the tropical fish spawn so much that it lags the server to the point of being unable to move. The question here is why? Is there some form or way I can limit it, like an "air" mob to fill in gaps?

MCreator Version 2021.3