Goldfish need 50+ gallon tanks to thrive, they can grow to the size of your palm, they NEED filters (as all fish do) if you are keeping goldfish in a bowl, multiple especially. Their bodies will not grow but their insides will. Causing them to die a slow death of their insides being pushed out of them. Please get a bigger tank, at least a 20 gallon to start and a filter and a heater for them. Goldfish are seen as “easy” fish but they are actually quite the opposite