Silver dollars are a schooling fish by nature and do best when kept in schools of six or more. A very peaceful shoaling species, they do not do well on their own, but even a large group will be skittish and timid when left without shelter.

They are peaceful enough to be trusted with much smaller fish than themselves, and yet they are robust enough to handle the company of much larger species. Peaceful large catfish such as plecos and doradids would be a good choice, as would many non-aggressive cichlids.

Silver dollars are hardy and easy to care for. Although this fish is fairly durable, the aquarist must maintain a very large tank for them. A school or six or more will require an aquarium of 75 gallons or larger. Silver dollars prefer subdued lighting, dark substrate, plenty of room to move about, as well as many good hiding places.

It’s advisable to use plastic plants or very sturdy live plants because they will eat most live plants. They do best in soft moderately acidic water, although they're not fussy about water conditions. Silver dollars are not overly demanding about water quality, though they do best in clean and clear, well-aerated, and well-filtered moving water.

Interestingly, silver dollars are in the same family as piranhas, but instead of being carnivores, they are almost exclusively vegetarian. Their favored foods include vegetable flakes such as spirulina, and leafy greens such as lettuce, watercress, and cooked romaine or spinach. They will also eat cooked vegetables such as peas and squash. When feeding any fresh food, take extra care to remove any uneaten portions promptly, as their decay will foul the water.

Even though the silver dollar prefers a vegetarian diet, they will also eat meaty foods as treats. They are especially fond of bloodworms, mosquito larvae (glass worms), and brine shrimp. If the silver dollars are in a community tank, watch them at feeding time to ensure that more active and aggressive fish don’t get the bulk of the food. Some silver dollar individuals can be rather timid in the crowd and can end up underfed as a result. The use of feeding rings will likely mitigate this issue.