The 400 I used in the past was float and sink, but then again it's produced in a different facility now, who knows what happened to the recipe. Here's the product description from Purina site:

Purina® AquaMax® Grower 400

100% nutritionally complete for starting fish and early growth phases for both carnivorous and omnivorous species. Purina® AquaMax® Grower 400 is a sinking product in a in a 3/32" extruded pellet with approximately a 50% float rate.

Many men go fishing all of their lives without knowing that it is not fish they are after. ~ Henry David Thoreau

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