To answer your question, there is a video of Rinpoche showing his giving blessings to fish in a pond, where he recites a few mantras for them. He uses one of the more famous mantras, "Om mani padme hum
", which is said to invoke the blessings of the Buddha of Compassion, Chenrezig. He also recites the mantra of Medicine Buddha, "Tayata Om Bekanze Bekanze Maha Bekanze Radza Samudgate Soha
You can watch the video here: http://www.youtube.com/watch?v=BQvvT4TfHrE
Rinpoche begins his blessings around 30 seconds into the video - just after the audio for the video kicks in.
I hope this of help to you.