Choosing between a terrarium and aquarium setup comes down to your budget, lifestyle, and how much maintenance you're willing to handle. Both environments support thriving plant ecosystems, but the costs and care routines diverge significantly. Here's what you need to know before investing in either.
Initial Setup Costs
Terrariums typically require less upfront investment than aquariums. A basic terrarium kit runs $30–$80, while quality aquariums start at $50–$150 depending on tank size. However, aquariums demand additional infrastructure: filters ($20–$100), heaters ($15–$40), lighting ($25–$80), and air pumps ($10–$40) are often non-negotiable. Terrariums need only soil, substrate, and optional LED grow lights ($15–$50).
For a beginner comparing just plants, terrariums win on budget. A $60 terrarium setup with moss, ferns, and pothos can thrive with minimal extras. An equivalent aquatic plant aquarium easily doubles that cost once you factor in filtration and lighting to support submersed plant growth.
Substrate and Soil Requirements
Terrarium plants grow in standard potting soil, coco husk, or sphagnum moss—all cheap and widely available. A bag of quality terrarium substrate costs $8–$15 and lasts for multiple tanks.
Aquatic plants demand specialized substrates. Nutrient-rich aquarium soil ($15–$40 per bag) supports rooted plants like Amazon sword and crypts. Inert gravel ($10–$25) works but won't feed plants long-term. Active substrates leach nutrients over time and need replacement every 2–3 years, adding recurring costs terrariums don't face.
Lighting and Energy Use
Terrariums work with indirect natural light or budget LED strips ($20–$50). Many thrive on a sunny windowsill with zero electricity cost. Closed terrariums create humid microclimates that reduce watering needs.
Aquatic plant tanks require 8–10 hours of daily lighting to prevent algae overgrowth and support photosynthesis. Quality LED grow lights for aquariums run $40–$120. Running lights 8 hours daily adds roughly $5–$10 monthly to electricity bills—a hidden cost many new aquarium keepers overlook.
Water and Maintenance
Terrarium maintenance is genuinely low-effort. Water once every 7–14 days by misting the soil. Closed systems recycle moisture internally, sometimes needing water only monthly. No water changes required.
Aquariums demand 25–50% water changes weekly or biweekly, depending on bioload and filtration. With a 20-gallon tank, that's 5–10 gallons of dechlorinated water each session. Factor in dechlorinator ($6–$12 per bottle, lasts months) and your time investment is substantial. Filters need monthly cleaning and replacement cartridges ($10–$20 every 4–8 weeks).
Plant Selection and Growth Rates
Terrarium plants (pothos, ferns, peperomia, begonias) are forgiving and widely available at garden centers for $3–$8 each. They tolerate inconsistent light and irregular watering.
Aquatic plants vary wildly in difficulty and cost:
- Easy, affordable plants: Java fern, anubias ($3–$6 each) thrive with minimal care
- Mid-range: Dwarf hairgrass, ludwigia ($5–$10) need moderate light and fertilizer
- High-maintenance: Carpeting plants like HC or Glossostigma ($8–$15) require CO₂ injection ($80–$200 setup), fertilizers ($15–$30 monthly), and precise lighting
Aquatic plant growth accelerates with CO₂ supplementation, but that's an optional expense that pushes total costs upward.
Fertilizer and Nutrient Needs
Terrariums rarely need fertilizer. Potting soil contains enough nutrients for 6–12 months. Optional liquid fertilizer ($8–$15 per bottle) extends plant health but isn't essential.
Aquariums benefit from both macro (nitrogen, phosphorus, potassium) and micro (iron, boron) fertilizers. Monthly fertilization costs $20–$50 depending on plant density and chosen products. Nutrient deficiencies cause algae blooms and plant melt, making supplementation nearly mandatory in planted tanks.
Long-Term Value
Terrariums are genuinely set-it-and-forget-it after 3 months. Annual costs hover around $15–$30 for replacements and optional fertilizer.
Aquariums demand ongoing investment: electricity, filter media, fertilizers, and occasional plant replacements push annual costs to $100–$300. The payoff is a visually dramatic planted aquascape and the ability to house fish alongside plants.
If you're comparing providers to source plants and equipment, Mercoly helps you find and compare trusted Live Fish & Aquatic Plants suppliers, making it easier to budget accurately for either setup.
Frequently Asked Questions
Q: Can I keep aquatic plants in a terrarium? Most true aquatic plants require constant submersion and will rot in terrarium humidity. Stick with semi-aquatic or terrestrial plants like pothos and ferns.
Q: What's the cheapest way to start a planted aquarium? Skip CO₂ injection, use inert gravel, choose hardy low-light plants like java fern and anubias, and accept slower growth—this cuts costs by 40–50%.
Q: Do terrariums need living fish or animals? No, plant-only terrariums thrive indefinitely. Some hobbyists add dart frogs or isopods, but plants don't require animal waste to fertilize.
Start exploring certified Live Fish & Aquatic Plants providers today to compare pricing and quality for your chosen ecosystem.