Decision guide

Planted Freshwater vs FOWLR Saltwater - Which Should You Pick?

Side-by-side comparison

Factor	planted	fowlr	Winner
Initial cost	$400-800	$800-1,500	Planted
Monthly cost	$25-40 (CO2 + fertilizers)	$40-60 (salt + RODI)	Planted
Visual style	Nature aquarium, Iwagumi, Dutch	Reef-edge feeling without the coral risk	Subjective
Maintenance	CO2 monitoring + plant trimming	Salt mixing + skimmer + protein checks	Planted (slightly easier)
Species variety	Hundreds of plants + fish	50-100 reef-safe fish	Planted
Upgrade path to next level	High-tech planted = same difficulty	FOWLR → reef = major upgrade	FOWLR (more progression)
Tank options	Standard rectangular tanks	AIO setups (Innovative Marine, Waterbox)	Even

Recommendation

Pick based on aesthetic - if you love aquascape design, go planted. If you love marine fish (clowns, gobies, wrasses), go FOWLR. Both are great mid-tier setups.

More decision guides

Browse all decision guides, the step-by-step setup tutorials, or the cost-of-ownership analyses.

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.