Help! Several of my Koi are suddenly lethargic the last 2 days
They've been super energetic and eating extremely well for the past few weeks. But suddenly yesterday I had two very lethargic baby fish (3" long) and now an adult today. There is no sign of any disease on them whatsoever, but their behavior doesn't look good. One was laying in a clump of algae, sometimes going to his side. What might be wrong, and what meds can I give them to help?