Rival-a-Day, Day 28
Delta
The delta is a species of carnivorous fish on Poseidon. It holds special interest to some marine ecologists due to its recently discovered relationship with another species with whom it shares a habitat, the Poseidon pink fish. The adult delta preys mainly on the smaller pink fish, only seldomly engaging in opportunistic scavenging.
Poseidon Pink Fish
Like the much larger delta, the Poseidon pink fish, described only some time after the delta was first catalogued, is a carnivorous species. It is a specialised paedophage, feeding exclusively on the egg clusters and freshly hatched larvae of the delta. The evolution of this closed cycle in which the two species predate each other and the mechanisms by which such an unstable situation is regulated has become the focus of study and debate.
Notes
Ecological rivalry, predator and prey, was an immediate association with Blue Planet when the Rival-a-Day concept came up.