How to Choose Your First Aquarium Size: Tank Volume, Space and Budget
The single most important decision you will make before buying a single fish or plant is the size of the tank itself. Understanding how to choose first aquarium size saves you from outgrowing a small setup within months or investing in a tank too large to maintain comfortably. At Gensou Aquascaping, 5 Everton Park, Singapore, we have helped beginners navigate this choice for over 20 years — and the answer is rarely what people expect.
Bigger Is Almost Always Easier
This sounds counterintuitive, but larger water volumes are more stable. A 100-litre tank dilutes waste, temperature swings and dosing errors far better than a 20-litre nano. Ammonia from a dead fish in a 15-litre tank can spike to lethal levels overnight; the same event in a 100-litre tank barely registers. If space and budget allow, start with the largest tank you can reasonably accommodate. For most beginners, a 60–120 litre tank is the practical sweet spot.
Assessing Your Available Space
Measure the exact spot where the tank will sit — width, depth and height clearance. Leave at least 10 cm behind the tank for filter hoses and cables, and 15 cm above for maintenance access. In an HDB flat, common placements include the living room TV console, a bedroom desk, or a dedicated aquarium stand along a corridor wall. Condominiums may have built-in shelving or balcony areas that work well, though direct afternoon sun on west-facing balconies causes algae and overheating. Always check that the floor or furniture can support the weight: water weighs 1 kg per litre, so a filled 100-litre tank with substrate, hardscape and stand easily reaches 130–140 kg.
Common Tank Sizes and What They Support
A 20-litre nano (25 × 25 × 30 cm) suits a shrimp colony or a single betta with plants. A 45-litre tank (45 × 27 × 30 cm) accommodates a small school of nano fish like ember tetras plus a few corydoras. A 60-litre setup (60 × 30 × 30 cm) opens up proper community stocking — a school of rasboras, a small group of bottom-dwellers, and a centrepiece fish. At 90–120 litres (90 × 30 × 36 cm or similar), you have room for lush aquascaping, multiple fish species and genuine creative expression. Beyond 150 litres, you enter intermediate territory where equipment costs, water-change volumes and stand requirements increase significantly.
Budget Considerations
Tank cost scales with size, but not linearly. A basic 60-litre rimless glass tank runs SGD 50–80 in Singapore. A 100-litre equivalent costs SGD 80–130. The bigger expense jump comes from equipment: a light suitable for a 90 cm tank costs SGD 80–200 versus SGD 40–80 for a 30 cm unit. Filters, heaters (if needed), substrate and hardscape all scale up. As a rough guide, budget SGD 200–350 for a complete 60-litre planted setup and SGD 400–700 for a 100–120 litre system including stand, light, filter, substrate and initial plants. These are starting figures — premium gear pushes the total higher.
Tank Shape Matters
Standard rectangular tanks offer the best surface area for gas exchange and the most usable planting space. Tall, narrow “portrait” tanks look dramatic but are difficult to light effectively at the bottom, limit fish swimming space, and make planting and maintenance awkward. Bow-front tanks distort the view slightly but provide extra volume. Cube tanks work well for nano setups. For a first aquarium, a standard rectangle with a 2:1 or 3:1 length-to-height ratio is the safest choice in terms of both aesthetics and function.
Weight and Structural Limits
HDB floors in Singapore are reinforced concrete and can handle substantial weight, but the furniture supporting the tank may not. A standard IKEA Kallax shelf holds about 13 kg per compartment — fine for a 10-litre nano, not for a 30-litre tank. Purpose-built aquarium stands distribute weight evenly through steel or solid-wood frames and are strongly recommended for anything above 40 litres. If placing a tank on an existing piece of furniture, confirm its load rating and ensure the surface is perfectly level; an unlevel tank creates uneven pressure on the glass seams, risking cracks or catastrophic failure.
Future-Proofing Your Choice
Most hobbyists upgrade within the first year. Knowing how to choose first aquarium size with that trajectory in mind prevents waste. A 90-litre tank may feel large at first, but once you discover aquascaping styles, plant varieties and fish species you enjoy, the extra space becomes essential. Conversely, starting with a tiny desktop tank and then upgrading to a 100-litre system means buying two sets of equipment, two lights and two filters. One well-chosen tank at the outset is almost always more economical than two sequential purchases.
Practical Tips Before You Buy
Visit a physical shop to see tanks in person — online dimensions do not convey real-world presence the way standing next to a 90 cm tank does. Local shops in Serangoon North, Clementi and along Thomson Road stock a wide range of sizes. Measure your space twice. Confirm your electrical outlet situation (you will need at least two to three plugs for filter, light and timer). And finally, buy the tank before the fish — cycling takes three to five weeks, giving you time to finalise your stocking plan while the biology establishes itself.
Choosing the right tank size sets the foundation for everything that follows. Drop by Gensou Aquascaping with your space measurements and budget, and we will match you with a setup that fits your home and your ambitions.
Related Reading
emilynakatani
Still Have Questions About Your Tank?
Drop by Gensou Aquascaping — most walk-in questions get answered in under 10 minutes by someone who has set up hundreds of tanks.
5 Everton Park #01-34B, Singapore 080005 · Open daily 11am – 8pm
