Keeping a fish only marine tank is no harder than keeping a tropical aquarium. The difference is you are using a salt and it requires a little more patience with testing.                               

Setting up the aquarium

  1. Choose a location for the aquarium away from doors and windows and in a room that does not get hot in summer. Water needs to be kept below 30 degrees.
  2. Wash gravel or marine grit with water before placing in the aquarium. The gravel needs to be around 3cm in depth or 4-5cm depth if you’re keeping lots of rock (to help keep the rock stable).
  3. Fill a large bucket or drum with water and add de-chlorinator (Prime). Add salt as per manufactures directions. Check with hydrometer and adjust if needed. If too high add de-chlorinated fresh water, if too low add more salt. Ensure salt is fully dissolved before adding to aquarium. Follow these directions until the tank ¾ full.
  4. Install the canister filter i.e. Fluval (don’t forget to add your extra filter medias such as Purigen, phosquard and Matrix). Add the aquarium heater as per manufactures instructions. Do not turn on.
  5. Retest salinity. Add fresh water if over 1.022, or more marine salt if below. Make up more saltwater in a bucket and add to the aquarium until water level is about 5cm from the top of the tank. This space is left in case more fresh water is needed to reduce salinity.
  6. Turn on filter. The water level will slightly drop. Set heater to 24 degrees. Let run for a few hours. Check Salinity again, adjust accordingly, and check pH level with high range pH test Kit. If below 8.3 Marine Buffer must be added. Fill tank with saltwater until water level is now about 2-3cm from top of tank. Mark water level with permanent marker on side of tank. If over time water drops below this level, and you have not removed any water, this will be from evaporation. Fresh water is then added to aquarium to refill back to the mark made. Always recheck with hydrometer.
  7. Install Lighting: As a fish only tank you don’t need any special lighting requirements, light is best kept to a minimum to prevent algae problems. Install lights as per manufacturer’s directions.
  8. Retest salinity and PH. Let tank cycle, using a good bacteria product  for a few days before adding fish. Start with something hardy eg. Damsels, Chromis or Clownfish.
  9. Monitor your PH, Ammonia and Nitrite once you start adding fish. If your Ammonia and Nitrite levels are at zero and your PH is at 8.2 you can add a new fish each week. If you add your fish gradually you will have minimal problems.
  10. Don’t forget to monitor your parameters every week. It is recommended to record these parameters so you can chart your tanks progress. A 25% water change when any high levels of ammonia, nitrite and nitrate are present will help reduce stress on fish. If you do encounter any increasing levels, please consult one of our aquarium staff to minimise the possibility of any fish loss.

Marine Aquarium Maintenance

  1. Clean aquarium sides weekly, with algae scrubber or magnet cleaner.
  2. Do 25% water change fortnightly, using a gravel vacuum, to clean the gravel. Have saltwater pre-made in buckets, ready to refill the tank. (Only use new buckets that have been set aside for your fish)
  3. Clean Filter as per instruction manual. A canister filter should be checked at least every 2-3 months and cleaned if water flow is greatly reduced.
  4. Test water parameters and adjust if required


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Monday to Friday 9.00am – 6.00pm
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Visit in-store where our helpful animal experts and delightful staff can assist with all your pet needs.