Every month.
one time a month
I would use a cleaning tube or use a bowl or something
It sounds like your fish has fungus over its eyes and skin. That indicates terrible water conditions. All fish need to have clean water. Change the water! Successfull fish keepers change at least a part of a tanks water weekly.
50 cm
They are fish tanks that have ocean water in them. The ocean water is almost always synthetic but can be real. People keep salt water fish, corals and many other things in these types of tanks.
For filtering aquarium water and fish tanks for healthy fish. This pet supply offers advanced pumping of the water and is not dangerous for fish reliably cleansing multiple fish tanks of varying size.
Water changes should be performed in fish tanks every 1-2 weeks to maintain a healthy aquatic environment for the fish.
they can be dripped into brackish water tanks
Of course not
10% water changes every week and 25% water changes every month is standard for all size tanks.
yes. they are nice, small, keep the water clean. but not big enough for most fish.
Using distilled water for fish tanks can help maintain a stable pH level, reduce the risk of introducing harmful chemicals or contaminants, and prevent the buildup of minerals that can be harmful to fish.