What is a filter? A filter can be fitted into any aquarium and is essential for keeping the water healthy and keeping your fish alive! It has a built-in pump which circulates and oxygenates the water, collecting all the waste into sponges or 'media' in a compartment inside. You change or clean the media when you do your monthly water change and maintenance. It's a bit like the way a tumble-dryer whizzes all the loose fluff into that little mesh bit that you have to empty now and again - the machine is doing all the hard work and you just have to empty what it's collected.
Which one to choose? There are hundreds of makes and models to choose from, but these here are our favourites. The Ciano range are physically very small (so not too ugly in your tank) but powerful and simple to use. They have optional extra cartridges that you can add or swap to solve particular problems, e.g. to treat algae or cloudy water. They are quiet, reliable and cheap - what's not to like!?
For larger tanks or where you have big greedy fish that produce a lot of waste (goldfish!) we would recommend the Eheim Pick Up range, which are like the Volvo of the aquarium tech world - no frills but very dependable and excellent value for money. The media is just a simple sponge - and unlike some flashy and over-priced rival brands, you aren't tied into buying expensive monthly consumables.
For even larger tanks you can choose an external filter, which has much more filter media inside so basically will do a better job for longer in between cleaning sessions. The Betta range is excellent value for money if you're after something cheap & cheerful. The Oase BioMaster range is at the other end of the scale, is the easiest to maintain and the price reflects the build quality and 4 year guarantee.
What is a heater? A heater is a glass or quartz tube with a heating element in to warm the aquarium water to the optimum temperature for your fish. Some fish don't need a heater and are happy at room temperature (coldwater species), but fish from warmer climates around the world (temperate or tropical) will need a heater to raise the tank water above room temperature. The heater has built-in thermostat so you set the temperature you want and it automatically switches on and off through the day to maintain a constant temperature.
Which one to choose? There are lots of makes and models to choose from, but these here are our favourites. The Betta range are cheap-and-cheerful with a 1 year guarantee. The Aqua One range is a step up in quality and come with a 2 year guarantee. The OASE HeatUp range are premium quality with a 3 year guarantee and are compatible with the Oase Thermo filters so they can tuck inside the filter units to make an all-in-one filter and heater unit.