PhotoIn my younger years when the goldfish didn't make it for whatever reason, they were simply flushed down the toilet. Perhaps it's not the most proper of burials but I'm not sure my parents really thought there were alternatives.

Many times people who own goldfish -- or any fish for that matter -- think when they no longer want them a lake or public water area may be a good alternative.

The problem is fish are pretty active sexually and they reproduce quickly. Someone who perhaps thought they were doing the best thing dumped a handful of goldfish into a lake in Boulder, Colorado, just three years ago and now they have reproduced into the thousands. If you remember from sex ed it only takes two.

"Based on their size, it looks like they're 3-year-olds, which were probably produced from a small handful of fish that were illegally introduced into the lake," Ben Swigle, a fish biologist at the Colorado Parks and Wildlife (CPW), told Live Science. 

The issue with so many goldfish is that the overabundance will create competition for native fish. It disturbs the food chain. There are about three or four fish species considered threatened or "species of concern" living downstream from the lake. If the goldfish end up going downstream it will affect spawning and also foraging resources.

Spreading disease

Disease is another concern because pet goldfish are not routinely tested for illnesses. These koi goldfish may be carrying viruses. They have the potential to kill thousands of other fish. Aquarium fish tend to get bacterial kidney disease and they could spread that throughout the area.

Scientists are currently considering three options for dealing with the exotic goldfish explosion. Officials could drain the lake and leave it dormant for a while, use electricity to stun the fish and then net them out, or use a chemical called rotenone that interferes with respiration to "remove" the fish.

Swigle said the plan is if they can remove them, they will feed them to injured hawks, ospreys and bald eagles, at a raptor sanctuary.

Looking to displace a fish? The American Veterinary Medical Association has guidelines for euthanasia of animals. You can check out their 2013  

Flushing fish is not recommended as the hardy fish can make it to natural waterways and wreak havoc. You don't want your fish responsible for creating 3,000 other fish.


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