A Vegetarian Piranha | Silver Dollar Fish
A large, peaceful, piranha like fish that works well in semi-aggressive tanks, the Silver Dollar is gentle giant with an average life span of 10 years and an average size of 15cm, however they are known to live longer and grow a great deal bigger if kept in large tanks with ideal conditions. Silver Dollars should be kept in groups of four or more, and ideally in a 120 cm (4 foot) tank.
These fish can become quite tame and gregarious over time, however Silver Dollars are quite notoriously skittish when they are young, and it is not uncommon for them to play dead when first added to a tank. Do not be concerned if they do not eat for a few days after being added to their new home, their appetite should return after a few days. Though they are vegetarian, if you add very small fish to a tank with large Silver Dollars, they may be eaten simply on principle. Remember the cardinal rule of fish keeping: if it fits in another fish's mouth, it is going to be food sooner or later.
Tank Mates and Tank Conditions
Their large body size makes them perfect additions to tanks with large fish, like cichlids such as Oscars and Jack Dempseys. If you already keep this type of large fish it is unlikely that you have a planted tank, as large fish tend to uproot and consume plants a great deal faster than they can be propagated in your tank. The Silver Dollar is a vegetarian fish and will strip plant matter in a matter of hours, so do not add them to a prized planted aquarium.
Having said that, the Silver Dollar's natural habitat is heavily planted, so if you put them in bare tank with only rocks and wood for friends, they are sure to be incredibly skittish. The solution? Fake plants, and lots of them. This won't just improve the appearance of your tank, but it will significantly lower stress levels on your fish.
Lighting should also be low to moderate. Don't flick on the light unexpectedly as you'll set them all off into panic attacks and they may hurt themselves.
Silver Dollar fish will eat almost anything, however they require some plant matter in their diet. Adding cucumber or spinach to their diet will keep them healthy and happy in addition to fish pellets and other fish favorites like brine shrimp and bloodworms.