The effects of the interaction of four fish species was studied in regard to their development and life history. The fishes were Fundulus heteroclitis, Cyprinodon variegatus, Lucania parva, and Menidida beryllina. The four species represented four types of feeding: C. variegatus, a herbivore; M. beryllina, a plankton feeder; L. parva, a small primary and secondary carnivore restricted to areas of dense vegetation; and F. heteroclitis, a moderate sized carnivore that feeds in a variety of habitats.
The findings were that C. variegatus was relatively immune from the competitive effects of the presence of the other fish species. In contrast, M. beryllina was negatively affected in growth and survival by the presence of the other species. C. variegatus has the unique ability to switch back and forth between herbivory and carnivory, based on food availability. This unusual capability is believed to be the reason that the species was the one that was least affected by the presence of the other species.
Hobbyists may wish to consider this and similar research when setting up a community tank. A mix of species with different feeding habits may help to reduce the odds of deleterious competition, as will the inclusion of omnivores.
Source:
Tropical Fish Hobbyist, July 1996, p. 8; reprinted from Journal of Fish Biology.
– G.C.K.A. Newsletter, March 1997