A 10-20 gallon bare-bottom tank with a cycled sponge filter, heater, PVC hides, and parameters matched to your display. Add the new fish via drip acclimation, dose Cupramine to 0.40-0.50 ppm for marine (or treat with general cure for freshwater), observe for 4-6 weeks of zero symptoms before moving to display.
See our complete Quarantine Protocol guide for full step-by-step instructions, treatment regimens, and the marine vs freshwater differences.