A 10-gallon tank is the entry point for stable freshwater aquariums. Realistic stocking targets: Schoolers: 6-8 neon tetras OR 8-10 ember tetras OR 8-10 chili rasboras OR 6 celestial pearl danios. Centerpiece options: 1 male betta + 6-10 cherry shrimp + 5-6 nerite snails. Shrimp-only: 20-30 cherry shrimp + nerite snails. What does NOT fit: goldfish (need 30+ gallons), African cichlids (need 55+), angelfish (need 55+), most gouramis except dwarf, plecos (most species reach 12-18 inches). Why "inch per gallon" fails: it ignores body shape (a 6-inch goldfish produces 10x the waste of six 1-inch tetras), territorial requirements, and oxygen demand. Use AqAdvisor or our stocking calculator for species-specific load percentages. Cycling first: never add fish to a brand-new 10-gallon - cycle for 3-6 weeks.
The full Q&A library answers the most-searched aquarium questions. Browse calculators, glossary, and disease database for related help.
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.
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.
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