Goldfish are often chosen by aquarium enthusiasts who want to keep a school of fish. However, you must select goldfish tank mates carefully to avoid potential problems. Though not all non-aggressive fish are suitable to dwell with goldfish, choosing the right species will help you create a harmonious aquatic community.
Tank Mate Requirements
There are specific requirements that tank mates must meet to even be considered as possible cohabitants for your goldfish. Goldfish are freshwater dwellers, which eliminates any types of saltwater fish as possible tank mates. Though goldfish are tropical, they do not thrive in warm water. Ideally, you should keep the water in your goldfish tank between 65 and 75 degrees Fahrenheit (18 and 24 degrees Celsius). When it comes to selecting tank mates for your goldfish, those that require warmer temperatures are not good options. The pH balance, or balance of acidity and alkalinity, of the water in a goldfish tank should range from around 7.0 to around 8.0, so the aquatic friends you select for your goldfish must also do well in such tank conditions.
If you are a goldfish lover, the best option for your tank is to fill it with other goldfish. Goldfish are omnivorous predatory fish that get along well with others of their kind. Your goldfish will do best with others that are similar in size and variety. Large, fancy goldfish like the telescope eye, fantail and lionhead goldfish swim and eat slowly. When kept with more common varieties such as the active shubunkin and comet, fancy goldfish may not be able to compete for food. In addition, because they are predators, goldfish will eat smaller fish. If you put small goldfish in a tank with larger varieties, the newcomers are likely to become dinner instead of viable tank mates.
Community Fish and Other Tank Mates
If you want a variety of community fish in your goldfish tank, choosing those that have similar temperaments and tank requirements will result in an aquarium that is beautiful, healthy and peaceful. White cloud minnows often do well with goldfish because they also prefer cool water. However, because they do not get very large, they are not recommended for tanks with fancy or large goldfish. Rosy barbs have similar temperaments as goldfish, and are also quite similar in appearance. Goldfish rarely prey on rosy barbs and live harmoniously with them. If you have a large tank, loaches do well with goldfish because they also thrive in cool water and grow too large to be considered prey. Zebra danios will cohabitate with common goldfish, but are too small to be kept with fancy or larger varieties. Another consideration for your goldfish tank is a non-finned tank mate. Freshwater snails make great companions for all varieties of goldfish. Not only do they help to keep the tank clean of algae and debris, but they are also not goldfish prey.
Tank Mates to Avoid
Though goldfish are predators, they are not aggressive fish. These passive community dwellers would be easy prey for aggressive fish such as cichlids and small freshwater sharks. When deciding on the best tank mates for your goldfish, leave aggressive varieties off your list. Though plecos are often kept with goldfish, these living arrangements do not always work out. Goldfish develop a layer of algae or "slime" on their bodies, which make them targets for sucking, algae-eating fish like plecos. Though they won't devour goldfish, plecos will pick or suck at them, causing sores and wounds that lead to life-threatening infections. Though neons are passive and get along with other community fish, their small stature puts them at risk for becoming prey to the majority of goldfish varieties.
Jennifer Lynn has been writing as a correspondent and reporter since 1991. She has written for numerous newspapers and currently writes as a correspondent for Gannett. Lynn has a Bachelor of Arts with a focus on English from Ohio University, where she also studied journalism at the E.W. Scripps School of Journalism.