Yeast in food

[dan-in-den]

I’ve seen several recipes for making your own frozen fish food that include yeast. But I’ve also noticed that several commercial fish foods state “does not contain yeast”.
Is yeast bad? Does anyone know of any articles/studies/sources of information regarding yeast in fish food?
If I drop pure bakers yeast into the aquarium, will it ferment my fish?

 

[dad]

Yeast has very poor nutritional values. I wouldn't,