Introduction. Selection of new cichlid specimens can be difficult for both the novice and advanced cichlid hobbyist. The increased availability of wild stock coupled with the steady production of tank-raised stock including F1, F2, and generations beyond can lead to confusion in selecting high-quality cichlids. Questions such as, "Are wild fish better?", "Are F1 better than F2?", are commonly raised but not always clearly answered. The purpose of this article is to define the different listings cichlids are commonly advertised under and provide basic guidelines for selecting specimens based on common sense and basic genetics.
Definitions. Cichlids advertised as "wild" are the easiest to define. These fish are collected from their native body of water and imported for the aquarium trade. Wild stock are almost always adults. Cichlids advertised as F1 (meaning first filial -from Latin for first generation) are the progeny of two wild cichlids and are one generation removed from the wild. Consequently, fish listed as F2 are the progeny of two F1 adults and are two generations removed from the wild and so on. A listing is not commonly given beyond two generations from the wild.
Several basic genetic definitions must also be considered in this discussion including inbreeding, outbreeding, and hybrid vigor. Note: when the term "hybrid" is used in this context it does not apply to the result of a cross of different species, but progeny from any cross of two parents of the same species. Inbreeding occurs by breeding within a line of related individuals. For example, breeding brother to sister in a line of a cichlid species. Inbreeding is used to develop particular traits (e.g. unique coloration) within a particular line. Repeated breeding within the line usually enhances the trait. Inbreeding, for example, may be responsible for the development of many "color forms" of peacocks (Aulonocara spp.) that have been imported from Europe (e.g. Rueben Red, German Red, Turkis, etc...). Inbreeding crosses are also used to isolate pure albino strains. Inbreeding tends to enhance a particular trait by making successive generations with increasingly homozygous (the same) alleles for all traits. This allows for a true-breeding (appearance in successive generations) line of the particular phenotype (expression of genetic information) that is attempting to be enhanced. The danger of repeating inbreeding is that alleles for all traits tend to become more homozygous including those which may code for undesirable recessive traits (such as genetic diseases). Thus highly inbred individuals tend to be less hearty. Outbreeding is the breeding of an individual to another (of the same species of course) from an unrelated line. The resulting progeny usually display hybrid vigor, a phenomena where the offspring usually demonstrate better growth and survival than the parental population. Hybrid vigor is thought to result from a higher proportion of heterozygous (different) alleles which reduce the likelihood of undesirable traits (e.g. genetic disease) being expressed and better ability to cope with environmental stress due to the heterozygous condition which may allow for adaptation to a range of environments.
Selection of Stock. The advantage of selecting wild cichlid fish includes a very high probability of being unrelated and characters, behaviors, and traits that have not been selected for by successive generations in captivity. The disadvantage of wild fish includes price and adaptability. Adult wild fish are imported from great distances away and command a relatively high price (maybe not by the standard of marine fish though). Wild fish may not be able to cope with the stress of transportation coupled with levels of dissolved metabolites (e.g. ammonia) and aggression in the aquarium far exceeding those of the wild environment. Certainly some species adapt more readily. In most species, several generations of captive selection usually produce fish better adapted to aquarium environment. This suggests F1 and F2 fish as good choices for cichlid aquariums. These fish will still retain some "wild" character and probably have a high degree of heterozygosity in their genotype, but have some selection for the ability to better survive the aquarium environment. These fish are also usually available as fry or adults and less expensive than wild fish. Selection of cichlid stock beyond F2 is largely a matter of careful observation. Examination of adults, if possible, will aid in selection of any cichlids including F1 and F2. The phenotype of the offspring generally resembles that of the parents. There are many examples of lines where the connection to the wild is unknown, yet high-quality fry are produced. In this respect, fish with an unknown distance may be better than wild, F1, or F2 if the adults are healthy and display a desirable trait such as unusually vibrant color. Recently, the importation and availability of wild cichlids has increased. This large influx of wild fish and corresponding wild genetic material probably guarantees some degree of heterozygosity in most species even amongst those individuals with unknown distance from wild fish. Thus keen observation of can identify high quality fish even when distance from wild is unknown.
Maintaining Genetic Diversity. The maintenance of genetic diversity is crucial for production of high-quality cichlids regardless of distance from wild of the parental stock. In the event, however unlikely, that wild sources of cichlids become absolutely unavailable, maintaining genetically diverse lines will be crucial to continued captive propagation. Maintaining diversity will reduce the probability that undesirable traits appear in successive generations. Outbreeding to unrelated lines assists in the maintenance of genetic diversity. A single outbreeding event, even within a highly inbred line, has marked effects on genetic diversity. Purchasing stock fish from two unrelated sources regardless of distance from wild will increase genetic diversity in the offspring. The likelihood of hybrid vigor, producing offspring with better growth and survival, is an added bonus. The expense and difficulty obtaining unrelated stock may be prohibitive for hobbyist breeders, but several options exist to locate unrelated fish for breeding. I often "bargain" shop at cichlid auctions for unrelated lines of fish and mix auction purchases with fry produced from my tanks to raise a new parent population. Involvement in local (Try www.fishlinkcentral.com to locate a local club) and national cichlid clubs is very helpful in obtaining high-quality (and possibly unrelated) stock at reasonable prices.
In summary, high-quality cichlids need not necessarily be wild, F1, or even F2. Selecting fish based on observation of adults will ensure quality stock for display or breeding. Maintaining genetic diversity by outbreeding is crucial in producing high-quality tank-raised cichlids.