Keep in mind these basic rules :- 1 inch of fish needs at least 1 gallon of water . All fish need a cycled filter running 24/7. Every tank needs to have at least 50% of its water changed weekly. Provided you have plenty of room and the fish you call "regular" are not tropical, goldfish will mix OK with most coldwater fish.
Betta fish are best as a solitary fish and are not compatible with goldfish.
other goldfish and mabey som catfish
you can put a put a clown fish or a angel fish but you have to have a lage a place to hold the fish because angel fish a a little territorial
goldfish, koi
goldfish mainly
you can fit alot of fish into a 60 litre tank. danios, regular goldfish and redcaps are probably the most common, maybe get a pleco for hygene
You can't put tropical fish with each other or they will eat eachother
no werdos of corse not
No goldfish would prefer to have a lower temperature than any type of tropical fish, however some goldfish can withstand higher temperature if they are slowly acclimated to it! But in the long run goldfish would be happy with other goldfish and tropical fish with tropical fish... there is a reason you don't see the goldfish with the tropical fish in a good aquatic store.
No i wouldn't recommend it
Definitely NOT! ARE YOU MAD? ALWAYS ask the goldfish for permission first.
No, goldfish are best with goldfish with the exception of weather (dojo) loaches, bristlenose plecos, and apple/mystery snails.Although goldfish can survive in warmer water temperatures, they are a "cold water" fish and not a tropical fish.