Filter Types

When you start your discus aquarium, you can consider several different types of filters. You may even choose to use more than one at the same time to maximize water turnover. In this article, we discuss the most common commercially available filters.

INTERNAL

Internal Filter

An internal filter is submerged inside the aquarium, usually stuck to the glass with suction cups. Internal filters are not often used in discus aquarium, unless when in conjunction with an external or canister filter. Internal filters usually do not provide a large enough surface area for enough bacteria to cultivate. They are useful however, if there is a ‘dead spot’ in your aquarium where water flow needs to be increased. Except for in that scenario, internal filters usually are not recommended for discus aquariums. 

EXTERNAL / CANISTER

These types of filters are the most popular amongst discus keepers, and are considered to be the “Rolls Royce” of filters. External / canister filters are placed outside of your aquarium, with two separate pipes entering your aquarium: one to suck water out and the other to pump filtered water back in. These filters provide massive surface areas for large amounts of bacteria to cultivate. They will keep your water quality higher, for longer. Even though they are substantially more expensive than most other filters, they are worth the cost. External/canister filters are highly recommended for discus aquariums.

TRICKLE

A trickle filter is best described as an external filter that specializes in biological filtration. While trickle filters are not necessary for discus aquariums, they can still be useful for discus tanks. They provide additional oxygen to the bacteria, thus enhancing nitrification. Since trickle filters are usually the most expensive, they are only recommended for discus keepers who are not concerned about the financial cost. However, to discus keepers who are trying to save money, trickle filters are NOT recommended. 

SPONGE

Sponge Filter

Sponge filters are small, air-powered filters that are submerged inside your aquarium. Though they are not suitable for display tanks, they are recommended for breeding tanks. They provide a balance between low current and relatively high water turnover. 

CORNER

Corner Filter

Corner filters are very similar to sponge filters. By sacrificing the layer of sponge on the outside, you gain more control over the filtration media that you’re able to fit inside. The water is siphoned directly through the filtration media, rather than through a layer of sponge first. This is good for the establishment of a bio filter or if you’re using chemical filtration such as peat moss. 

QUESTIONS

• Which types of filters do you use in your discus aquarium?
• Which filters are most commonly used in discus aquariums?
• How are sponge filters different from corner filters?