Custom Fluid Hooks

I have made a custom fluid (whose Material is Material.water -- more about that later).  And placed blocks of it into the world to test what happens when the player is inside it.  Just sitting there, the player doesn't drown (as I would expect from reading the EntityLivingBase.onEntityUpdate() method).  When I swim upward, there is a point (and it is very short-lived) where the breath meter shows up, but it goes away quickly.

My question is two-fold.  First, what else would I need to do to get people to drown in my fluid?  Second, is there not some hook to allow customizing an entity's behavior in a custom fluid?  I want entities (well most of them) to drown in my fluid, but not be able to swim in it, or see the little blue bubbles.

Here is my Fluid and Block code:

public class MyFluid extends Fluid {
public MyFluid(String fluidName) {
	super(fluidName);

	this.isGaseous = true;
}	
}

public class MyBlock extends BlockFluidBase {
public MyBlockextends (int id, Fluid fluid) {
	super(id, fluid, Material.water);
	this.setCreativeTab(myTab);
}
@Override
public boolean isAirBlock(World world, int x, int y, int z) {
	if (world.getBlockId(x, y, z)==this.blockID) 
		return true;
	return super.isAirBlock(world, x, y, z);
}
}