Types of Compatible Freshwater Goldfish

Freshwater goldfish are hardy fish that can thrive at a relatively large temperature range. Many goldfish keepers set up outdoor ponds or large indoor aquariums for their fish, and having a variety of fish can make a tank much more interesting to watch. Several types of goldfish can live together, and some other fish species can be housed with goldfish.

  1. Fish Size

    • Goldfish of very different sizes should not be housed together, even if the two fish are the same species. A goldfish's adult size is determined partially by the size of her aquarium, so any goldfish species can grow very large. Tosakin and panda moor goldfish, two relatively large types of fish ranging from 4 to 8 inches, shouldn't be housed with other goldfish. Similarly, goldfish with flat bodies shouldn't be kept with goldfish with rounded bodies. The common goldfish and comet goldfish are compatible-sized species that frequently share a tank.

    Habitat Requirements

    • Goldfish are classified as cold-water fish, but some require warmer temperatures than others. Before housing any two varieties of goldfish together, check the care and habitat requirements for the fish. Never put fish that have different water temperature or feeding habits together.

    Fish Disposition

    • Some goldfish are slow and not aggressive, while others tend to nip other fish's tails and swim quickly. Don't keep fast- and slow-swimming fish together. Fantails and orandas can sometimes share a tank if they are the same size, but should never be placed with common or comet goldfish. Bubble-eye goldfish can often be housed together, but may be attacked by goldfish without bubble eyes.

    Compatible Non-Goldfish

    • Although they look like goldfish, koi are technically a different species. These fish should not be housed with fancy goldfish, but may do well with comet or common goldfish if the fish are similarly sized. Snails, loaches, corys and white clouds may also thrive with goldfish. However, follow the same precautions as when keeping different types of goldfish together. Never house aggressive fish such as cichlids with goldfish.

    Fish Safety

    • When introducing new goldfish -- whether of the same or a different species -- quarantine the new fish for several days in a separate tank. This gives you time to monitor the new fish for any health or behavior problems. If the fish seem lethargic, have damaged fins or behave abnormally, don't add them to your other fish tank until you consult a fish veterinarian.