The basics
Choosing a tank size, and where to put it
Go as big as your space and budget allow. More water dilutes waste, so conditions stay steadier. The RSPCA says a tank should be larger than about 40 litres, and Practical Fishkeeping calls 60 to 80 litres ideal for a first tank.
Remember the weight: a litre of water weighs a kilogram, so a 100 litre tank holds about 100kg of water before you add glass, substrate and rock. Use a purpose-made stand or a level, sturdy surface. Keep the tank away from windows, radiators, vents, speakers and doors, and leave room for a lid, which keeps heat in and fish in. Think about a socket you can reach, and about how you will get an arm and a bucket in for water changes.
Complete kits usually bundle a filter, a light and sometimes a heater, but no kit includes everything, so check what is missing before you buy.
Choosing fish next? Start with our tropical fish page.