Goldfish are one of the most common house "fish" pets.
A regular goldfish
would generally only grow up to a couple of inches due to their being kept in
small bowls, but, if they are kept in a pond the comet goldfish can grow up to
24 inches! And weigh up to an amazing 9.9 pounds.
A comet usually only lives 6-8 years. But they can live up to 20 years, the record for a goldfish life span is 49 years!!!
The reason why we
picked a goldfish for our experiment is because frankly they're not picky eaters
and they do NOT have to be fed meat, and are used to eating plants, algae and
yes, 
their
own faeces.
The comet also thrives in temperatures near freezing!
