I thought I'd start this forum off by posting a few suggestions for compatible goldfish companions. (Secretly, I just want to be the first poster in a new forum!
)OK, from everything I've read, some suitable companions for goldfish include:
White Cloud Mountain Minnows or Common Minnows: these are true shoaling fish so at least 5-6 of them are best; one on its own will feel vulnerable, even with a goldfish buddy. They only grow up to about 3" max though, so may turn into a snack for very large goldfish! They also need excellent aeration.
Weather loach, or Dojo: algae eater and very peaceful, though possibly not the most attractive creature! May actually befriend the goldfish rather than just co-existing with them. These fish are also escape artists so keep the tank fully covered.
Koi: only in outdoor ponds, never in tanks! Their space requirements are massive... but so worth it!
Orfe: a slim, streamlined fish that loves to cruise the upper layers of water. If you keep one in a tank be sure to keep it covered, and if you keep some in the pond don't be surprised to fine one lying on the lawn - orfe love to jump! They also need excellent aeration.
Tench: again, really a pond fish rather than a tank fish as it can grow well over a foot long. There are two forms - the common brown / grey, and the cultivated golden form. Peaceful, likes to lurk at the bottom in clumps of plants.
Bitterling: lovely blue/silver colouring, grows about as big as a common GF. Peaceful, graceful fish. If you want to breed bitterling, you need to put fresh-water mussels in the tank as these fish only lay their eggs inside mussel shells.
Medaka: Tiny, brightly coloured fish, able to withstand extremely cold temperatures (will swim beneath ice). Peaceful. Keep at least 3 together.
Just some ideas to kick around....
EDIT: just noticed jdude beat me to the first topic!
