While wild-caught can be an okay thing, this isn't always the case. More than a few species have become endangered due to the over-collection in the wild. This happened to celestial pearl danio until someone figured out how to breed them. It is currently happening to the beautiful redline barb (Puntius denisonii
) although efforts are being made to breed them. Over-collection in the wild coupled with habitat degradation is causing their numbers to plummet. Another incident were wild-caught fish are bad is with the blue-eyed panaque, a rare loricariid catfish. They are found in an area of South America controlled by drug lords; if any wild fish is exported from that area, the proceeds go to these drug cartels (read more
). So the lesson to this little rant is some wild caught fish like cardinal tetra are good, but others are bad. Research before you buy.