Stocking your marine tank

Taking the mayhem out of marine fish keeping


stocking your marine tank


For most people this is the most exciting part of the hobby. It’s now that all the careful planning and seemingly endless waiting will come together and start to reward all your hard work.


By now you should have a clear plan of what you’re intending to keep, an aquascape you’re pleased with teeming with bacteria on standby to start filtering, and the whole thing looking like a blank canvas ready to be adorned with all the corals and fish of your choice.


Cycling your marine aquarium


Adding Clean up crew


Adding fish


Adding corals


Adding anemones

Whether FOWLR, soft corals, hard corals or a mix of all three, things still need planning. Your stock list needs to be planned to minimise the risk of your marine tank inhabitants killing each other. Big fish will try and eat little fish; some fish will declare the entire tank as their own and make it their life long duty trying to make life difficult for everything else that shares their glass box. Soft corals will give off toxins than can wreak havoc with hard corals, hard corals can send out stinging missiles that can kill their neighbours. Whilst all this is going on chances are you have probably picked up some hitchhikers in your live rock that will be trying to catch various tank inhabitants for supper.


The point I’m making is that whilst you have visions of sitting back and relaxing at the tranquil scene you have strived so hard to create, what you are actually watching is a slow motion battle of life and death. It’s up to you as a responsible fish/coral keeper to ensure these battles are kept to a minimum.


Not only do fish fight and eat each other with alarming regularity and corals spend their days trying to kill their neighbours but then you go and mix fish with corals and yet more battles begin. Some fish are fine with soft corals but will go through hard corals like a dose of salts. Even if your fish aren’t eating your corals they may be perching on them, using them as look out posts to survey their territories. This can cause the delicate coral tissues to recede and can sometimes be fatal.


With all this in mind careful planning of your tank stocking is an obvious must. This is also why it’s beneficial to create a long term stocking plan or else you could find yourself having to rehome half your stock if you suddenly decide to radically change the species you want to keep.


A few internet searches will bring up plenty of fish compatibility charts. It really is worth doing some planning in the early stages to avoid heart ache later on.




Helpful tips




A marine tank is like a mini battle ground, many of your tank inhabitants don’t particularly want to live with each other, careful planning is essential to reduce friction and therefore stress within your tank.


If you are intending to run a mixed tank, remember that soft corals can release toxins that can be very detrimental to the health of some hard corals.



Stocking - in a nutshell

You may have already picked up some unwanted hitch hikers in your live rock, if fish or invertebrates start going missing it could be worth setting up a bottle trap to see what is roaming about the tank undetected.

Aggression in a marine tank is not only unpleasant to watch but will increase stress levels for the fish which can lead to increased risk of diseases.

Remember to consider your tank inhabitants feeding requirements when deciding your stocking list. Slow feeders, for example like pipe fish, garden eels and seahorses will not fare well in a tank with fast moving tangs.

Some fish like gobies like to sit on hard corals and survey their surroundings, this can eventually lead to the death of the coral.

Don't underestimate the length of some sweeper tenticles used by some LPS corals. These often only come out at night so may not be too obvious on a recently purchased specimen until it's fully settled.