Quarantine for Marine Fish

There are a many different ways to set up and quarantine fish. However, a quarantine tank doesn't have to be elaborate. We have listed equipment required for a basic quarantine tank.


  • Quarantine Tank: For small to medium sized fish (less than 4 "), a 10 gallon tank.  For larger fish (over 4"), a 20 or preferably 29 gallon.
  • Heater: Any reliable submersible heater correctly sized for the tank used.
  • Thermometer: A submersible thermometer.
  • Filtration: A sponge filter driven by an inexpensive air pump or hang on the back power filter appropriately sized for the tank. * The sponge filter or power filter cartridge should be placed in the main display aquarium or sump for a minimum of two weeks prior to use in the quarantine tank allowing bacteria to colonize on it "pre-seed."
  • Refractometer: We recommend a refractometer to measure the specific gravity of the saltwater. A swing-arm hydrometer can be used. However, they are not as accurate.
  • Test Kits: The basics of Ammonia, Nitrite, Nitrate and pH. If medication such as Copper will be used, a Copper test kit is required.
  • Medications: It's a good idea to have some medications on hand. There are numerous products available for illnesses/diseases encountered for which the hobbyist will have to research the product to use based on observation of the quarantined fish. Always dose medications based on manufacturers recommendations for specific illness/disease. Also note, medications have an expiration date, and should be replaced accordingly.
  • Lighting: Any inexpensive lighting. Place the light so water will not splash on it or its cord, and where it will not overheat the water.
  • Cover: Some fish are known to jump out of tanks; therefore, a cover should be used.  A simple glass aquarium cover will do, or egg-crate used for lighting will work providing the fish in quarantine cannot fit through the squares.
  • Shelter: Providing shelter for the fish in quarantine will help reduce stress. A simple PVC pipe (with smooth edges) sized for the fish to hide in, or plastic plants will work.
  • Salt Mix & RO/DIPremix 5 - 10 gallons of saltwater for 24 hours prior to use. Having enough premix for a 25 % water change, plus extra for an emergency water change is always a good idea. Always keep your saltwater aerated or stirring with a powerhead, never let it sit motionless.
  • Dedicated Quarantine Supplies: It's best to have supplies such as nets, specimen containers, and siphon hoses for quarantine use only to avoid possible cross-contamination.

Receiving New Fish for Quarantine:

Use the following guide to set up your quarantine tank just before bringing home your new fish.

  • Placement: Place your quarantine tank in a quiet area, but within an area where the fish can be easily observed.
  • Fill Tank: Fill the quarantine tank with saltwater that matches the salinity of the main tank. This can be comprised completely of the fresh premixed saltwater made 24 hours in advance, with some fresh premix and some from the main tank, or completely from the main tank.
  • Install Equipment: Install the heater and set to the temperature of the main tank. Place the thermometer and "pre-seeded" sponge filter in and hook up its air pump.
  • Provide Shelter: Place the shelters in the tank. If PVC pipe or fittings are used, make sure any rough edges have been sanded off.
  • Acclimate: Acclimate the new fish with water from the quarantine tank.

Important Notes to Remember:

  • Test: Test for ammonia daily
  • Top Off: Replace evaporated water with RO/DI water (freshwater - NOT saltwater) daily.
  • Water Changes: Perform regular water changes, and emergency water changes if ammonia levels start to rise. If using medications, follow manufacturer recommendations. If using a copper medication, do not use ammonia remover products as this can increase the toxicity of some copper medications.
  • Observe: Observe fish frequently for signs of stress, illness/disease, and to make sure it is eating properly.
  • Illnesses/Diseases & Medications: Research to identify any possible illnesses or diseases encountered and medicate appropriately.
  • Transfer to Main Tank: Transfer your quarantined fish to the main tank only if it is eating properly, and shows no signs of illness or disease after a minimum of 3 weeks.

Enjoy your new fish, and know your patience and diligence will reward you with beautiful and healthy saltwater inhabitants!

Store Location

205 West Golf Road
Schaumburg, IL 60195
(847) 885-7333

Main Menu