Which things you should put into aquarium?
Filter, heater, light, plants, decorations.
Which fish you cannot put together because of the tendency to attack each other?
Tetras
Goldfish
Corydoras
Bettas.
What is the aquarium heater for?
It is for keeping the right temperature in aquarium.
What is aquaristic?
It is a popular hobby, practiced by aquarists, concerning the fish in aquaria.
Which fish can be kept in both inside and outside environment (e.g. pond)?
Goldfish
Bettas
Tetras
Corydoras
What is the filter for?
The filter is for keeping water clean.