Reef-safe classification is critical for reef tank stocking. Fully reef-safe fish: clownfish, most damsels (with caveats), anthias, fairy + flasher wrasses, basslets (royal gramma), most blennies, gobies (yellow watchman, diamond), cardinalfish, dragonets. Reef-safe with caution: dwarf angels (50/50 - depends on individual), most tangs (occasional polyp nip), large wrasses (eat shrimp + small fish but not corals), Foxface (rare clam nip), anthias. NOT reef-safe: large angels (Queen, Emperor, French - eat coral), butterflies (most species), triggers (most species - eat shrimp + crabs), pufferfish (eat snails + clams + corals), cleaner wrasses (poor survival rate). Reef-safe inverts: cleaner shrimp, peppermint shrimp, hermit crabs (small species), turbo + nerite + cerith snails, sand-sifting starfish (with caution). NOT reef-safe inverts: coral banded shrimp (eat ornamentals), most large hermit crabs (eat snails), serpent stars (eat small fish + crabs at night), most large starfish (Linckia, Choc Chip - eat coral). NOT reef-safe meds: any copper, formalin (in reef), praziquantel okay but most others lethal to inverts.
Reviewed by the Fast Aquatics husbandry team · Updated May 2026
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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.
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