Rosies are actually less tolerant to water conditions than koi. In the tub where I am growing my hyacinths, I have had to restock the rosies three times this Winter. Only the most hardy of them survive... Plus the fact that they are bred as feeders and are in extremely poor shape when you buy them from the store. I think if I get the dojos out of my pond this year, there will be some surviving rosy babies which should be a lot hardier than the stock I get from the store.
Like CE, the only time I have had fish jump out of the pond was during the first few days. My original pond was partially above-ground, so it was impossible for the fish to even flop back in. When I built my new pond, I made sure to include large rocks around the edge to help knock the jumpers back in the water, and so far I haven't lost anybody else.
@Event Horizion - Gotta love the creeping jenny (aka 'moneywort')! That is my primary ground cover around my pond, and some of it in the water manages to stay green through the Winter, despite the occasional solid freeze into the ice.
I have one plant of bog bean, and it has come back for the last couple years, but it never really seems to do very well. I don't know if the fish are eating it faster than it can grow, or if its in too deep of water. Its sitting in about 8" now, but I might try moving it back to a little shallower water this year and let it grow downhill to wherever it wants. I've never seen mine flower.
With the recent changes to my pond liner, and the water being 2" deeper now, I've been moving my shallow-water plants around. Some of the snake grass got moved to the river bank, and I really hope to see those take off this year. The stuff grows wild around here, yet I can't seem to get it to do very well in my pond, but now I actually have a lot of area that I can put plants who want their crowns out of the water.
