Although freeing small fry or other beings that will not be killed in the near future is also liberating living beings, they are not lives saved at the point of being killed. To engender great merit and to be deemed a genuine form of fearless offering, lives saved should be those that are about to be killed such as the assorted fish sold in the marketplace.
[Excerpt from Luminous Wisdom Book Series 1: The Right View ~ Liberating Living Beings]