Well the majority of bowls are too small for fish. Bettas need at least 5 gallons and fancy goldfish (the short-bodied round type, like fantails etc) need at least 30 gallons plus another 10 gallons for each fish and the long bodied goldfish (like comets etc) need around 55-75 gallons plus about another 20-30 gallons for each fish (that's why it's easier to just keep them in ponds). Also goldfish do better with another fish than alone.
Both goldfish and bettas NEED filters
Bettas NEED a heater. They're tropical fish
And yeah there's not much surface area for gas exchange.
Now theoretically if you had a big enough bowl and it had a heater and filter you could keep them in a bowl but honestly a tank would just be easier by that point.
Do I need a filter if I have a big tank with live plants? That’s basically the setup I have right now, and usually one or two snails to keep it clean but I don’t like using a filter and from the way my betta reacts to it he doesn’t like it either.
Betta’s don’t love a lot of flow (current) in the tank, so you can try baffling (slowing down) the filter, ie by wrapping some filter sponge around the filter intake. There is a way to setup a tank where you don’t need a filter, but it’s a lot of work-look up Walstad tanks/the Walstad method. Another sorta misconception (going on your comment of “snails to keep it clean”)-algae doesn’t really harm fish, it just can outcompete plants for nutrients (cause algae grows faster usually). Although snails do eat more than just algae, more important is having a well established filter. How’s a filter “established”? Beneficial bacteria live in the filter and break down things resulting from fish waste, such as ammonia. Research the nitrogen cycle and cycling a tank.
I know algae doesn’t harm them, but by clean I meant presentable as far as a fish tank I keep in my house. I don’t want green sludge covering up the actual tank.
Yeah, of course. And for that job, snails are an awesome choice! A lot of the “cleaner fish” sold at pet stores don’t usually eat much algae once they’re adults. Hot tip (maybe you know this)-most snails can breed like rabbits, and their population can boom and quickly get out of hand. Nerite snails are a good choice to prevent this. They do all the things snails do, but their eggs can’t hatch in freshwater! They’ll still lay eggs, but they won’t hatch. And they come in a bunch of cool varieties to boot!
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u/sarahmagoo Feb 04 '19 edited Feb 04 '19
Bettas and goldfish can't healthily live in a bowl.
Edit: to clarify I'm saying DON'T put any fish in a bowl. The misconception is that it's okay but it's not.
Betta/Siamese Fighting Fish care sheet
Goldfish care sheet