Hi Hollie – your fish sound adorable! I’m glad you’re enjoying your fish keeping hobby. I find fish are great for relaxing after a stressful day at work. 🙂

Hi Damon,

Thanks for your comment! You ask some pretty good questions.

Common and comet goldfish actually grow very large and are kept in ponds for this reason. Comets can quickly grow up to a foot long, and some have even been known to grow over 20 inches. They also require more space than fancy varieties, so if you’re looking to keep more than one comet, you’ll actually need a 40-gallon tank rather than a 30 (add +20 gallons for each additional comet).

Fancy goldfish, on the other hand, usually reach 6 inches, depending on the breed. So that’s a pretty big size difference! I’ll cover more about this in a later article, but just know that goldfish do best with other goldfish of the same size and body shape.

As for dividers, I suppose you could if you had the space and a really large aquarium (100-gallon), so that you could fit at least a couple goldfish on either side (2 comets on one end and 4 fancy goldfish on the other). But I really wouldn’t recommend it. I suggest to instead build a pond for your comets and keep the fancy goldfish indoors if you wanted to separate them. Or, choose between the two and decide which breeds of fish are more appealing to you.

Best of luck!

Christina

Are there any other reasons to keep different types of goldfish apart? Could you use a temporary divider or something during feeding time to make sure both types of fish get their fill?