Short answer

Budget setup: $500-800 for a 30-gallon nano (tank, light, skimmer, sump, heater, salt mix, RO/DI). Mid-range: $1,500-2,500 for a 65-90 gallon mixed reef. Enthusiast: $3,500-7,000+. Ongoing costs: $50-150/month for salt mix, supplements, electricity.

In depth

Saltwater costs decompose into three buckets: tank + equipment (one-time), livestock (one-time but cumulative), and operating costs (monthly).

Equipment cost by tank size

Item 30-gal nano 65-90 gal 120+ gal
Tank + stand$200-350$500-1,000$1,200-2,500
Reef-spec LED$150-300$400-800$1,000-2,000
Protein skimmer$100-200$200-400$400-800
Sump + return pump$150-250$300-500$500-900
Powerheads$50-100$150-300$300-600
Heater + controller$30-60$60-120$100-200
RO/DI unit$80-150$150-250$200-400
Live rock + sand$80-150$200-400$400-800
Total equipment$840-1,560$1,960-3,770$4,100-8,200

Livestock budget (typical mixed reef stocking)

  • 30-gal nano: $300-600 (clownfish pair, gramma, firefish, 5-8 corals, cleanup crew)
  • 65-90 gal: $800-1,800 (8-10 fish, 15-25 corals, full cleanup crew)
  • 120+ gal: $2,000-5,000+ (12-15 fish, 30-50+ corals, including premium specimens)

Monthly operating cost

  • Salt mix: $25-60/month for water changes
  • Supplements (alkalinity, calcium, magnesium): $15-40/month
  • Food: $15-25/month
  • Electricity: $15-50/month depending on tank size and equipment
  • Carbon, GFO, filter media: $10-30/month
  • Total: $80-200/month

More questions

Can I run a reef tank without a sump?

Yes for nano-size tanks (under 30 gallons). Hang-on-back skimmers (Aquatic Life HOB, AquaMaxx HOB-1) work for nanos. Tanks 40+ gallons benefit dramatically from a sump - it adds water volume, hides equipment, and provides a refugium for nutrient export.

Is a reef tank cheaper than a freshwater planted tank?

No. Reef tanks cost 3-5x more in both equipment and livestock than equivalent-size planted freshwater tanks. The justification is the visual and biological complexity reef tanks support.

Aquarium-keeping fundamentals

Whatever specific topic brought you here, four fundamentals govern long-term aquarium success: water quality, parameter stability, biological filtration, and species-appropriate husbandry. Skip any one and the others struggle to compensate.

Water quality: ammonia + nitrite at zero, nitrate under 30 ppm freshwater + 10 ppm reef. Test weekly with API or Salifert kits. Use our water parameter checker to score your readings against your tank type.

Parameter stability: stable wrong parameters beat fluctuating ideal parameters. Most fish tolerate a wide pH range if it's stable. Sudden swings of 0.4+ pH or 5+°F kill fish faster than chronic suboptimal values. Use temperature controllers (Inkbird) + automated dosing for consistency.

Biological filtration: the bacterial colony on your filter media + rock + substrate is the engine. Never replace all media at once. Use our filter turnover calculator to size correctly.

Species-appropriate husbandry: research adult size, territoriality, diet, and tankmate compatibility before purchase. Use our tank stocking calculator + compatibility guides.

Frequently asked questions

How long does an aquarium take to set up? 4-6 weeks for full cycling + first stocking. Use our cycle ETA calculator + how long does cycling take.

What's the best aquarium for beginners? 20-gallon long. Big enough for parameter stability, small enough for budget + space. See beginner picks.

How often should I do water changes? 25-30% weekly. See water change frequency Q&A + water change calculator.

Why does my fish keep dying? 5 leading causes: uncycled tank, wrong species pairings, no quarantine, undersized tank, neglected water-change schedule. See full diagnosis.

Related resources

Saltwater livestock · Freshwater livestock · Coral catalog · Care library · Q&A library (222) · Glossary (127) · Disease database (50) · Calculators (29) · Interactive tools (7) · Husbandry deep-dives · DIY projects · State legality directory