WET BEHIND THE EARS?
Our section for beginners to the world of fishkeeping.
It’s not that long ago that the only real choice of aquarium substrate was the colour of the gravel you were planning on using. This was largely due to the preferred filtration method which was ‘undergravel’ filters — basically the whole substrate was your filter and to best achieve this, relatively coarse gravel was needed.
Probably the most popular alternative to gravel, sand can give a lovely, natural look and many fish will enjoy digging around in it for food, or even burying themselves under it. The colour range is typically more limited, but natural white, golden and even black sands are available. Especially fine sands can be sucked into external filters, potentially causing damage to their impellers, so be sure to site the intake a little higher to prevent this. Like fine gravel it can become compacted, so diligent maintenance is essential.
Yes, it’s still popular and makes an excellent choice for many aquariums. The range has expanded hugely and offers all sorts of choices in terms of size and colour. You can get everything from the classic ‘Dorset pea-shingle’ (a selection of rounded, naturally coloured granules with sizes typically from 1cm to 1mm) to bright, artificially coloured substrates, graded to a uniform size and available in a literal rainbow. Fine sizes can compact while larger, coarse types can become clogged — using a gravel cleaner when doing your water changes will help prevent this happening.
While undergravel filters still exist, (and can work very well if maintained correctly) they are seldom seen outside fish shops and the boom in planted aquaria has led to an equivalent explosion in variety when it comes to what you choose to put on the floor of your fish tank.
Here are a few of the basic options.
Planted tank substrates
While you can successfully grow many plants in plain gravel or sand, to achieve the lush growth you see in many of the beautiful ‘aquascapes’ that jump out of the pages of PFK every month, you’ll need a specialist planted tank substrate.
These typically come in two varieties; complete substrates or base layers.
Complete substrates are, as their name suggests, complete and are intended to be used alone. They are made to contain an optimum mix of nutrients combined with the perfect grain size to promote plant health and growth. They are available in an increasingly large range of colours and sizes and are probably the most expensive substrate choice, but for good reason.
Base layers are generally a nutrient rich substrate intended to be put on the tank base, and then topped off with a cheaper, inert substrate like sand or gravel. These substrates are considerably cheaper to buy than the complete types, but the base and top layers can end up getting mixed together due to the actions of digging fish or during other aquarium maintenance.
Sand looks very natural but needs regular maintenance.
Planted community tank with a gravel substrate.
You’ll need a specialist planting substrate for a result like this.