Platys can sometimes be kept in a bowl, if the bowl is big enough and in a warm enough area. Generally, though, fish bowls should be banned and not used.
A fish bowl is not a solution its what you keep your goldfish/ beta fish in :P
it depends how big the fish bowl is
it is always good to get some kind of filter for your fish, but natural ponds dont' always need one. the filters will keep out some bad bacteria though, and keep your fish healthy longer, and allow you to actually see them. goldfish are very hardy and can withstand quite a bit.
The cheapest way to keep a goldfish is to keep it in a fish bowl.........as long as the bowl is big enough the fish will be happy there.
Betta
I guess you mean Puffer fish. If so, then the answer is definitely NO! IMO there is no fish that should be kept in a fish bowl.
No
The best candidates are Betta fish and Paradise Gouramis
Although it may well be possible to keep one for a short time (1"of fish NEEDS 1 gal of water)I believe it is cruel to keep any fish in a 'fish bowl'. Even a Betta.
You don't. You put it in a pond. Koi grow to over 24". To keep one in a bowl would be terribly CRUEL!
Only if you like the Buddha statue, and it's made from something that won't alter the pH of the water.
no. a fish bowl is way way way too small for any fish, let alone a group of tiger barbs and mollies.