They are too small and tropical. There really aren't any schooling fish that would go with them. There's a reason the hobby is divided into sections...Tropical and coldwater...otherwise it'd just be "Freshwater."
I've also read that goldfish/koi can carry some diseases that do not affect themselves but can infect tropical fish species that are kept with them.
Even the smallest goldfish can catch something like an oto. Someone was mentioning that they've seen pics of a very small moore that had an oto stuck in it's mouth, resulting in the oto needing to be cut out..
It's just generally not a good idea.
I've also read that goldfish/koi can carry some diseases that do not affect themselves but can infect tropical fish species that are kept with them.
Even the smallest goldfish can catch something like an oto. Someone was mentioning that they've seen pics of a very small moore that had an oto stuck in it's mouth, resulting in the oto needing to be cut out..
It's just generally not a good idea.