Filter died and just some questions

[megabyte]

Hey people, so today whe cleaning my 20 gallons tank I noticed my filter is dead. As I was not the person who set up the tank I need some advice. ( sister did it she now lives 13 hours away) I plan on buying the same filter. I am also in the huge need of changing my sand. Do I do this at the same time just to get it over with, or should I wait? And anther question how soon after I change my filter can I change my interior I am no longer a fan of my sisters old sponge bob theme and wish to change it. I currently only have 6 fish in there (1 algea eater, 1 corydoua, 3 tetras, and 1 guppie) when I do the sand change do I take them out or leave them in?



Please reply soon <3

 

[megabyte]

Hello back again, so I replaced my filter to find out my heater and my light broke (shortage) how long will my fish be able to survive without those? I don't get paid for two weeks and I'm worried about asking my parents for money.

 

[osolynden]

The heater is a pretty big deal. They can live without a light.