My RCS sit on top of plants and roam freely around my tank with 25 cardinals and 5 guppies. I have never seen them lay their eyes on the RCS. It's funny when they are all fighting for the same algae wafer though.
Just keep the fish well fed. Shrimp swim fast and are smart enough to hide in plants (hopefully your tank is planted enough)
Yeah, thx for the feedback, i don't think my guppies are bothering my rcs. And btw, i have an alright planted tank, I just need the plants to grow in a bit since they are quite small, especially my rotala rotundifolia because I just trimmed it and the 5 peices that i propanged(or w.e) are starting to grow, I already see roots and a side sprout from each one.
I put RCS and guppies in the same tank about 2 months ago. Just had our second set of shrimplets about a week ago. They all seem to roam freely. I am sure some of them ended up as gourmet fish food, but overall the colony is growing.
I have one tank with endlers, amanos and cherry shrimp and another with guppies and yellow shrimp. I keep a moderate supply of java moss in the back of both tanks and see a lot of baby shrimp activity in the moss. I would highly recommend using some moss for any shrimp breeding colony.