If you’re a goldfish owner, you may be considering a fish friend for your pet. Goldfish are compatible with hundreds of fish breeds, however, it’s not quite as simple as selecting a random fish and putting it in the same tank as your goldfish. Different fish require different conditions, for example, goldfish are freshwater fish, so the fish you choose need to thrive in this environment, too.
Temperature isn’t the only factor you need to consider, either. You also need to think about tank size, feeding habits, and temperament. So, let’s have a look at the things to consider before adding another fish to your goldfish tank…
Things to Consider Before Adding a Fish to Your Goldfish Tank
As we said, goldfish are freshwater fish. Fancy goldfish should live in temperatures of 68° to 74° F, while Comets and Shubunkins should be kept in water between 60° and 70°F. Goldfish also prefer water where the alkalinity is higher than the acidity, so water with a pH between 7.0 - 8.4 is best.
It’s therefore important that you choose a fish that also favors these conditions, for example, a tropical fish that is used to warmer water is not going to be the ideal tankmate for your goldfish.
This is also an important consideration, as it’s unfair to cram multiple fish into a small space. To provide for more fish, you should either ensure your tank is big enough or you should purchase a larger one.
While some people may think it’s OK to keep goldfish in bowls, these are not sufficient in size. The goldfish you buy from the store are still young, and therefore you need to accommodate not just their current size, but their potential size, too. Common goldfish can easily reach 10 inches in length and Fancy goldfish can grow to be 8 inches long.
It’s recommended that Common goldfish and Comet goldfish are kept in a tank measuring at least 4 feet long, with a volume of at least 30 gallons, adding an extra 12 gallons for each additional fish. The bottom line is, the bigger the better, as the more space your fish has, the more they can swim and thrive.
Fish that Make Good Tank Mates for Goldfish:
This is probably the easiest option, as you know that your tank set-up will suit other goldfish as well as the one you already have.
The main thing to consider when adding more goldfish to your tank is to ensure they’re of a similar size. Goldfish who are fin-nippers or boisterous should be avoided.
There’s also the risk that larger goldfish can eat smaller ones, or that slower-moving ones, such as Fancy goldfish, won’t be able to compete for food.
Goldfish of similar sizes can get along, however Commons, Comets and Shubunkins may become too viscous for smaller Fancy goldfish, and may need to be housed in a separate tank.
That said, if you do well-match your goldfish, they will thrive with companionship, as goldfish are gregarious, meaning they like to hang around together.
White Cloud Mountain Minnows
These fish are cold-water fish, so they’re well-suited to the same environment as goldfish.
They need company - as they’re schooling fish and don’t do well on their own - so it’s a good idea to add at least 3 minnows, although 6 is ideal.
White cloud mountain minnows are very fast and can usually outswim goldfish, meaning it’s less likely that they’ll become prey.
Similar to White Cloud Mountain Minnows, Rosy Barbs are schooling fish and need to be kept in groups of at least 6, otherwise, they become very stressed.
They thrive in the same water conditions as goldfish and grow between 4-6 inches long on average, so they’re too big for your goldfish to eat. Rosy Barbs usually like to mind their own business and they’re certainly not the aggressive types.
Rubbernose and Bristlenose Plecos
While regular plecos are known to suck the slime off of goldfish’s scales, Rubbernose or Bristlenose plecos make great tank mates for goldfish as they’re calm and won’t agitate other fish.
They’ll also keep your tank squeaky clean - as they spend most of their day eating algae from rocks and grass.
These fish live in the same conditions as goldfish and are fast swimmers, so they’ll be able to out-swim goldfish and will be able to compete for their food.
They’re a good match for regular goldfish, however, you should avoid mixing them with Fancy goldfish as they are so fast that they may eat all of their food.
Zebra Danios thrive with company as they’re schooling fish, and should be kept in groups of at least 6.
Fish that Don’t Get on Well with Goldfish:
- Common Plecos - known to suck the slime coat off of goldfish which can cause infection.
- Corydoras - also prone to sucking the slime coat from the goldfish and can be aggressive.
- Cichlids - aggressive predators.
- Bettas - prefer a warmer environment, prone to fin-nipping, and can be aggressive.
- Other species of goldfish. More specifically, Common goldfish do not mix well with Fancy goldfish as these are much slower and more fragile.
- Tetras - prefer warmer water, and don’t cope well in messy water.
- Mollies - tropical fish and also very aggressive and will most likely attack your goldfish.
Goldfish can thrive with the company of other fish, however, you must choose a fish that is compatible with your goldfish.
There are lots of things to consider, such as the temperature of the tank, ensuring your tank is big enough to accommodate more fish, and finally, checking that the fish will get along.
Goldfish can grow to be quite big, so they need a companion(s) who can match them in size so they don’t become prey or a fish that is fast enough to at least outswim them and compete for food.
It’s best to do your research so you select the best companion for your goldfish, and it’s a good idea to consult an aquarium expert before you purchase your new fish, too.