Other goldfish of a similar breed are compatible tank mates.
- Goldfish require cooler water temperatures than many other varieties of fish.
- Goldfish can pick on/snack on slower fish or creatures in your tank. ex: apple snails.
- Goldfish are aggressive opportunistic eaters and can out compete smaller or slower fish.
The last point explains why you should not mix slow moving or poor seeing goldfish breeds like the celestial, bubble eye or telescope with a strong swimming shubunkin, ryukin or comet.