Never. You should change the water a few times a week if the bowl is not filtered, but do't completely clean the blwl or wyou will destroy the benifical bacteria that converts ammonia and nitrite to nitrate and o2
you should change it every week so it will always be clean.
A geckos water bowl should consist of clean water at all times. This means the bowl must be changed and clean every day. In most cases a water bowl will evaporate if a heating lamp is present but if not, that water will turn stale, possibly grow mold and is possible to make your animal ill. The animals habitat should be cleaned monthly at a minimal.
I clean my male betta's 1gal bowl at least once a week
Once a week
no, only if your fish is appearing ill.
A dog should always have a clean bowl of water available. Water needs to be freshened daily or more often.
Feed them once daily, clean 50% of their water at least once a week, and for inhanced comfort, add water condition to the tank (you can get it at almost any pet supply store). DO NOT PLACE BETA in with other FISH. They will fight and kill the other fish. DO NOT place a Beta in with another BETA unless you are breeding them. A Beta is a solitary fish that will fight its own reflection so try not and place anything in the bowl that is to shiny. Also a Beta does not require much space so a small bowl will suffice. Beta also should be checked EVERYDAY and make certain that it is still in its bowl if it has jumped out. get a larger bowl, it usually means it feel to confined. At night Beta's and I believe it is the males I am not certain if the females do it as well, however they build a nest of bubbles at the top of the bowl and they hover under the nest and sleep. The reason for this behavior, dunno I am not a Beta, however in all the years I have owned them. They have done it. So if you see a bubble nest at the top, its quite normal.
every 3-4 weeks
A fish bowl is not a solution its what you keep your goldfish/ beta fish in :P
A bird bath should be cleaned based on the amount of usage. If your bird bath is frequently used, then you should clean it every week or so. If it isn't, then it should be cleaned at least monthly.
they can live in goldfish bowls i have always kept my beta in a goldfish bowl and my last beta lived between 4-5 years in a goldfish bowl.
I have a Beta for the first two weeks we did not think it was eating it's food .But we continued to clean it's bowl regularly and feed it just the same ;it's been 3 months now.Fish is doing fine.