Uzrok grbavosti je
1. Fizička trajna ozljeda - u slučaju da je grbavost određenih jedinki bez daljnjih napredovanja, tj. stanje je uvijek isto: hvatanje, i ozljeđivanje mladih ženkica od vječno napaljenih mužjaka... Nema razloga za eutanazijom ako ribica normalno funkcionira, osim ako ti na živce ne idu invalidi- a tu se pozivaj samo na vlastitu savjest.
2. iscrpljenost organizma radi stalnih trudnoća i/ ili starosti (jer su stalno trudne... da, i ribe mogu imati nešto nalik osteoporozi i druge bolesti povezane s lošom prehranom kao i ljudi) - u slučaju da se grbavost pogoršava.
Bliže srodstvo u konstantnom križanju najviše djeluje na skraćivanje životnog vijeka grupe ribica iste vrste bliskom srodstvu. Nije neuobičajeno da su ribice iz domaćih mrijestova prekrasne, zdrave, vesele i pitome - no, žive sve kraće ukoliko se krv svakih nekoliko generacija ne osvježi. To nije slučaj samo kod riba, nego i rasnih pasa, mačaka, konja... Pa i ljudi - dapače inbreeding je ribama i ljudima vrlo blizak pojam iz prakse (u mali offtopic ću otići kasnije..)
Ako imaš namjeru uzgojiti određeni liniju karakterističnog izgleda - nemaš što drugo nego križati bliske srodnike s odabranim karakteristikama. Naravno da križanje srodnika nećeš dopustiti ukoliko primjerci imaju vidljivih i poznatih nasljednih genetskih bolesti, mada neke nije niti to sprječavalo. Inbreeding je nemoralan sa suvremenog ljudskog stajališta, no ne tako davno imali smo drugačije mišljenje:
Egyptian marriages conventionally occurred between an older man and younger woman), we find that almost all possible brother-sister marriages were, in fact, contracted. This strongly suggests that sibling marriages were not only common but the preferred norm.
The documents also demonstrate that sibling marriages sometimes continued through two and three generations, and that the overwhelming majority of brother-sister marriages produced children. This practice lasted for at least three centuries and ended only when the Romans discouraged the custom by withholding Roman citizenship from persons continuing the practice.
Another example of a brother-sister incest custom is presented by Edward E. Evans-Pritchard when writing about the African Azande. "[W]hen a boy reaches puberty he may take his sister and with her build their little hut near his mother's home and go into it with his sister and lay her down and get on top of her—and they copulate" (1974, p. 107). Middleton (1962, p. 603) also notes that Azande kings married their daughters and that father-daughter incest was common among the Thonga.
Among the Greeks, Keith Hopkins notes that "[t]he Athenians allowed marriage between half-siblings of the same father but different mothers; the Spartans allowed marriage between half-siblings of the same mother and different fathers" (1980, p. 311). The ancient Hebrews permitted a similar practice as noted in the Old Testament by Abraham's marriage to his half-sister Sara.
John M. Goggin and William C. Sturtevant (1964) list eight other societies that allowed sibling marriage among commoners as well as thirty-five societies that allow sibling marriage between persons of high status.
In addition to cases of sibling marriage, there is abundant evidence of close inbreeding provided by human isolates—small isolated communities where the degree of inbreeding is determined by the size, extent, and length of isolation of the population (Leavitt 1990). These small isolated communities were numerous in the past and represent the norm for preagricultural Paleolithic societies.
Read more: Incest/Inbreeding Taboos - Sibling Marriage And Human Isolates - Family, Marriages, and Sister - JRank Articles http://family.jrank.org/pages/854/Incest-Inbreeding-Taboos-Sibling-Marriage-Human-Isolates.html#ixzz36svo4EV3Dapače bez inbreedinga ne bi bilo današnjeg suvremenog čovjeka, rasa, podrasa i krvnih grupa... Time su se mnoge bolesti istrijebile (monogene bolesti su vrlo rijetke), nagomilalo bogatstvo, poticano je u ropstvu koje i danas postoji, kao i loze, klanovi...
Zakon RH dopušta brak između strina i nećaka, ujaka i nećakinja - a nisu li to bliski srodnici? Ne vidim da je bilo referenduma po tom pitanju, a niti interesa za isti. Jedino se raspravljalo o spuštanju dobne granice dopuštenog sexa s maloljetnicima... Zanimljivo, nije li?
Bez brige grbave ženke itekako će imati zdrave i vesele potomke, no preporučam ti odvajanje samo zato što su manje pokretne i stoga podložnije stresu radi koga mogu oboljeti. Iskreno vjerujem da su to mehaničke trajne ozljede.