Antwan, ich is a primarily stress related disease due to improper tank maintanance. Certain fish are definately more prone to it than others, and certainly every aquarist has battled ich at some point in time, but if tank conditions are tip-top for the particular speices they house, then they should not die of ich. All fish carry ich, just like all humans carry staph, but the organisms only reach disease potential when the immune system of the host is compromised in some fashion. You could blame it on purchasing unhealthy fish from the start, but most fish, even if purchased covered with ich, can be medically treated to full health by the dedicated aquarist. Increasing salinity in a freshwater tank would be a good remedy for ich infested Columbinan catsharks, perhaps combined with some Quick-cure malicate green treatment and daily water changes to remove free-swimming larval stages that hatch off. It is the getting them to feed part that's a bit difficult, but most fish will respond to fresh foods, (ie thawed frozen stuff), even when sick, and water quality of course should be drinkable. The fact that your fish died all around the same time is an indication of a suspect tank upset, either from cycling or from some drastic stress factor such as sudden ammonia spiking or extream temperature fluctuations. Columbian sharks are too delicate a species for an un-cycled tank, and should only be added to an aquarium with fully established biofiltration and stablized chemistries. Even then, transport stress is a good cause of ich in a skiddish species, and fish like that should be maintained in a q-tank before introduction to the main population.
The theories of convergent and divergent evolution does not apply to domesticated animals. Certainly humans have twisted the "form fitting function" theory of adaptation to suit their own aestetic pleasures. Such is the case with brachycephalic canines, like pugs, which are breed with pushed in faces that mimic the face of a human, at the expense of the dog's ability to breath comfortably and eat properly. Centuries of unnatural selective breeding is what produced the domestic canine, whos only predator is the combustion engine. When compared to the wild wolf, cyote, or jackle (the three ancesteral canine lines from which it is believed domestic dogs arrose from), domestic canines:
1) live longer: The average life-span of a domestic dog, depending upon breed, is 15-20 years for toys, and 9-15 years for medium and large breeds. The averagel life-span for a grey wolf in the wild is believed to be 6 - 10 years while in captivity they have been known to reach 20 years.
2) have greater litter survival: Almost 99% of all puppies born to a domestic dog reach adulthood, compared to perhaps the 10% of all wild born wolf pups.
3) less parasite load and disease: Routine preventive medicine contributes to the health of domestic canines. All wild animals carry some parasites which at any moment are prepared to take advantage of a compromised immune system.
4) live less stressful lives: Domestic canines do not suffer droughts, famines, domanice battles, extreamly cold winters, extreamly hot summers, nor do they have to hunt, migrate, maintain territory, evade predators, contend with environmental polution and habitat loss, or in many cases even rear puppies. All these things are considered stress factors, and wild wolves are assulted with them on a daily basis, which contributes to immune system compromise and shorter life spans.
I could go on and on, but I think I've made the point clear. Domesticated animals, and even wild animals kept in captivity, usually fair much better, live longer, and are healthier, than their brethern in the wild. Of course, doing all of the above primarily depends upon how well they are cared for by the individual responsible for their husbandry. I probably should've compared domestic bettas to wild bettas, it would make the same point.
Not all flying lizards are equal, and the point you bring up is the Darwin theory of divergent evolution (aka the Galapagos finches), which does not apply in domestication, nor has anything to do with the comparison of domestication vs wild survival rates. Even if you wish to state, of course, that a pacu in the wild will grow larger and live longer than a pacu in an aquarium, you need to then remove the "stupid, novice aquarist" factor. Pacu kept in major aquariums that have their every wish catered to definately live longer and grow larger than wild pacu, and certainly fair better than the pauc in a 55 gallon home tank. Also, pacu bred in captivity will have greater fry survival than wild pacu, where 95% of the fry never reach adulthood due to predation or environmental factors.
~~Colesea
The theories of convergent and divergent evolution does not apply to domesticated animals. Certainly humans have twisted the "form fitting function" theory of adaptation to suit their own aestetic pleasures. Such is the case with brachycephalic canines, like pugs, which are breed with pushed in faces that mimic the face of a human, at the expense of the dog's ability to breath comfortably and eat properly. Centuries of unnatural selective breeding is what produced the domestic canine, whos only predator is the combustion engine. When compared to the wild wolf, cyote, or jackle (the three ancesteral canine lines from which it is believed domestic dogs arrose from), domestic canines:
1) live longer: The average life-span of a domestic dog, depending upon breed, is 15-20 years for toys, and 9-15 years for medium and large breeds. The averagel life-span for a grey wolf in the wild is believed to be 6 - 10 years while in captivity they have been known to reach 20 years.
2) have greater litter survival: Almost 99% of all puppies born to a domestic dog reach adulthood, compared to perhaps the 10% of all wild born wolf pups.
3) less parasite load and disease: Routine preventive medicine contributes to the health of domestic canines. All wild animals carry some parasites which at any moment are prepared to take advantage of a compromised immune system.
4) live less stressful lives: Domestic canines do not suffer droughts, famines, domanice battles, extreamly cold winters, extreamly hot summers, nor do they have to hunt, migrate, maintain territory, evade predators, contend with environmental polution and habitat loss, or in many cases even rear puppies. All these things are considered stress factors, and wild wolves are assulted with them on a daily basis, which contributes to immune system compromise and shorter life spans.
I could go on and on, but I think I've made the point clear. Domesticated animals, and even wild animals kept in captivity, usually fair much better, live longer, and are healthier, than their brethern in the wild. Of course, doing all of the above primarily depends upon how well they are cared for by the individual responsible for their husbandry. I probably should've compared domestic bettas to wild bettas, it would make the same point.
Not all flying lizards are equal, and the point you bring up is the Darwin theory of divergent evolution (aka the Galapagos finches), which does not apply in domestication, nor has anything to do with the comparison of domestication vs wild survival rates. Even if you wish to state, of course, that a pacu in the wild will grow larger and live longer than a pacu in an aquarium, you need to then remove the "stupid, novice aquarist" factor. Pacu kept in major aquariums that have their every wish catered to definately live longer and grow larger than wild pacu, and certainly fair better than the pauc in a 55 gallon home tank. Also, pacu bred in captivity will have greater fry survival than wild pacu, where 95% of the fry never reach adulthood due to predation or environmental factors.
~~Colesea
