In the Amazon River there lives the pacu, a relative of the piranha. The pacu has a similar shape to the piranha but can grow to be much larger, weighing in at over 50 pounds. And also similar to the piranha are its set of teeth, but with an interesting twist. They look more like a set of human molars as the pacu primarily feeds on nuts and seeds which it crushes and grinds up with its teeth and powerful jaws.
Because of its piranha-like appearance but less than hostile manner, the pacu pops up in aquariums around the world from time to time. But as it ultimately outgrows most home habitats, they sometimes find themselves cast aside in local rivers or lakes. As supposed herbivores, it would possibly seem that the pacu would be a harmless addition, but there apparently are reports of this fish being responsible for the deaths of two men in Papua New Guinea by castrating them - eeyeowch!
So, it is with a measure of concern to city officials, residents and tourists, as we enter the warm summer months, that pacus were reportedly being caught by fishermen in Lake Lou Yaeger in Illinois. With more and more bathers entering the lake to escape the heat, the possibility of someone being bitten begins to increase. As Pete humorously reported in his blog, one key lake official was taking a less than alarmist position regarding the pacu.
"Lake superintendent Jim Caldwell, sounding a bit like the Amity Island mayor in Jaws, assured that everything's OK, adding that he has a small swim in the lake regularly. It was about then that you half-expected the scary theme music to begin playing."
Responsible home aquarists always consider the repercussions of disposing of any fish - large or small, teeth or no teeth - in local waterways. Many fish that are sold to fresh and salt water aquarium enthusiasts are, in fact, juveniles only a few weeks old. This makes them fragile and mortality can be high. But if the fish survives and thrives, the owner often can find that they have a fish that is soon outgrowing its habitat.
When I was in my junior high school years, I owned several aquariums in which I prided myself in having a dazzling array of fish to impress my folks and the neighbors. (My friends weren't all that interested. It was a bit nerdish, in an age of pre-computer nerds.) There was a local tropical fish store which had some nefarious connections and was able to procure for me a pacu, which I didn't have for too long; the poor thing could barely turn around in the tank. The shop was also able to get me a series of actual piranhas, which are illegal for regular consumers to own, buy, sell, or trade (I'm guessing the statute of limitations has expired). The laws existed to prevent a piranha from ending up in the local watering hole and, even as a kid, I could appreciate that since one nearly bit my finger when I was cleaning the tank one day.
So, I can understand the fascination that home aquarists can have in owning exotic fish, but there is a very serious side to their activity that demands responsible decision-making. Many fresh water fish are raised rather than caught in the wild, but some of those fish can grow to be quite large with hungry appetites. Salt water fish can also be raised but some are caught in the wild and at great harm to the reef from where they came. Collectors will sometimes use chemicals or poisons that stun the fish for ease of capture. Unfortunately, the poisons kill the coral and damage the caught fish's internal organs so that it's life expectancy is shortened.
While one can debate the value or purpose of home aquariums, there should be total agreement that transplanted fresh or salt water plants and animals can have unforeseen consequences on marine ecosystems.