From Creatures Wikia
Upon injection, the lower Norn Meso is flooded halfway with fresh water, then some of the critters and plants from the Norn Terrarium pond are injected into it. Like in their home, the Stickletrout have a tendency to die of starvation, and so the included Fish Feeder (in the form of a dragonfly nymph) prevents this. A similar agent in the form of a dragonfly performs a similar function to the Fish Feeder for the dragonflies. It is similar to the Pond Fish Food for Creatures 3, except that it uses different sprites and works only with Docking Station. Due to the C3 origin of The Pond's Ecology, it needs to have Creatures 3 installed before it will work, although it is a DS Standalone agent.
The Pond is availible for download at Creatures @ CU7.