I found four alive in my tank! Managed to get a few pictures.
This one hanging out on the sponge filter, reflected on the wall. There's another shrimp under the filter- can just barely see its rostrum- and I saw a third one on the wall behind the elodea thicket.
They are very hard to spot because the legs, antennae (so long) and most of the body is clear. See this guy on the wood- very difficult to see. They have a strong pale dorsal stripe with symmetrical markings on the tail- which I never noticed before.
And part of the body looks green inside- I'm guessing because they are eating algae! I looked very closely but only could find four. I know two had just molted the day I put them in the tank- maybe those got eaten by the fishes well I'm glad to have four, however long they last.