Hi jo3olous, I have 3 fantails, 1 black moor and a blue oranda. All of them are about an inch and a half long, very small. My local store, which has a good reputation assured me they were fine together. My biob is about 15 us gallons I believe.
So is that 5 fish in total? Don't want to offend you, but it sounds like your store either has a very oldfashioned way of housing fish, or they just wanted your money.
A General rule of thumb is 1 goldfish for every 10G of water, I believe 15 is optimal for the first, then 10G more for each additional fish. Keep in mind things look okay now, because they are only 1.5inches in length, but goldfish grow rather large as adults anywhere from 10-16 inches. These buggers also have a big bioload (they eat and poo a lot) which is why the tank space is so necessary. It would be stressful for a fish to be swimming in its own waste, no?
Even if you have 3 fish, they will quickly outgrow that tank. It's an either or really. Your fish can manage to outgrow the tank or they will die prematurely of stress.
My recommendation: Research on your own next time before making a purchase, fish stores generally lack proper knowledge, or they will say anything to get your money. Return the goldfish or trade them in for fish that will not grow so large and do not require so much space. Or last, keep them and take good care, so that you can prepare for a larger tank in the future. The 1st suggestion should be done always, either solution for your current problem is optimal.
You can keep the fish as is too, but that might not be the healthiest option for your fish. Welcome to the tank, you came to the right place. There are many others who can also give you great advice. *GOLDFISH*
***Just wanted to note the bio-orb. I heard it was an amazing unit for housing fish, and the filtration was excellent along with the oxygenation. But they are so darn small and so expensive!
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