Categories: Shellfish Tanks, Todd's Top Tips658 words2.7 min read

Todd Fish Guide to Operating a Shellfish Tank


Errin Todd


March 15, 2016


Shellfish Systems are used to hold lobster, crab or langoustine.

The lobster tanks can be used for short or long term storage.  Most fishermen use the system to hold their stock until they have a full load to take to the local buyer or merchant.  A shellfish system comprises tanks and a filter.  This guide is based on our Todd Fish lobster tank but will be useful for any system you have.

Test strips water quality ph

If you are using tap water with a salt mix check whether your water has chlorine or chloramines in it.  A blog coming soon on this topic.  Mix your sea water in a separate tank and leave it for at least 24hrs, if possible you can add an air stone to mix the water more.  We would always recommend using natural raw seawater where possible.  Not only is it cheaper, it is also better for the animals.  Fill the tanks and filter with seawater, test the water for temperature, pH, salinity and ammonia. Take any action to ensure the water is within the optimum parameters (see ammonia and pH).  You should test your water at least once a week.

Check the pumps are running and the water flow rate is good.  Ensure the air pump is working and there is plenty air bubbles in the tanks.  Check the filter does not need cleaned e.g. foam in the protein skimmer or blocked sponge filter or media.  Our new triple filter has easy tell-tale signs that it needs cleaned.  If you are using a chiller check it is switched on and the temperature reading is correct.  Have a look at the water checking it is clean, clear and moving well around the tank.  It should smell like the sea.  If it’s ‘fishy’ there is something wrong.  Finally have a listen to the system – if there is any problems usually you can tell by an unusual sound.  Eventually you will get to know the ‘normal’ sound of your system and this will be your first indicator if something is wrong.

Filters take time to mature.

Triple Filter for Lobster Tanks

Triple Filter for Lobster Tanks

Add your stock gradually.  We recommend only ¼ of the full capacity and only add more when your ammonia levels are within acceptable parameters.  There is no shortcut to this process.  Slowly does it.  It can easily take 6 weeks to mature a biological filter.  If you are installing a new system keep this in mind and make sure it is matured before the start of the season.  Once the filter is mature you can fill the tank to the full capacity.  If you overload the tank there will be problems.  Overloading will void your warranty.  Any time there is a change e.g. water change, stock rotation, water temperature change, warmer weather, new supplier or problems with your stock check the water again.  If your ammonia levels are high go back to the start of the maturation process i.e. reduce stock levels and test regularly.

Gently does it with the animals.  Treat the livestock like the valuable, quality commodity they are.  Do not drop, throw or crush the lobsters and crabs.  Any shocks create cumulative stress in the animals.  Any vast changes in temperature, pH or salinity will also cause stress. A stressed animal is vulnerable to infection, disease or death.  A weakened, limp animal is also worth less.  Handle the shellfish with care and they will thrive in a Todd Fish system.  There are many studies into the effect of handling on shellfish.  It is just common sense to be careful.

Errin Todd with Lobsters

Errin Todd with Lobsters

Once the animals are in the system, keep checking the water quality regularly. Check all your stock daily and immediately remove any weak, dying or dead animals before they spoil the water.  In future blogs, we will look at maintenance schedules, cleaning advice and more about water testing. Healthy and happy lobsters are tastier!

Best Fishes,


Errin & Laura