First Introduction – Fish Or Invertebrate

The majority of aquarists decide that the first introduction to their aquariums should be a fish yet does it need to be this way.

I fully understand why this happens and perhaps this is due to historic reasons where aquarists used hardy fish to assist in the cycling of their aquariums. Something which I am glad to say is not done anymore. Perhaps it is the movement and colour of the fish which draws the eye. There are many reasons as to why people choose a fish as the first inhabitant of their aquarium. It uis of course not up to me to sway their decision in any way but perhaps people believe that a fish has to be the first introduction.

On another note if the aquarium is a fish only aquarium then the aquarists will of course be introducing a fish first!

For the aquarist with a reef aquarium however there is another choice especially when live rock is used as the filtration but it does not matter what filtration is employed. Live rock even when matured correctly is not very sterile and therefore may carry opportunistic parasites. When a fish is caught in the dealers it is put under immense stress due to the catching, the bagging, the transport etc. When the fish is introduced to the aquarium its immune system may be lower than normal and in a reef tank filtered via live rock it may become prey to opportunistic parasites.

I appreciate that the above can happen at any time in the aquariums life however at the very start the aquarist is learning and if a fish is lost at the very start then this is sad for obvious reasons however the aquarist’s confidence in the aquarium and his/her own abilities and may give up the hobby.
There are certain fish which are more resilient than others however a lot of these fish – damselfish for example can become problematic later due to the aggressive nature and it is very hard to remove a fish from an aquarium with live rock in it!

Another method at the very start instead of fish is introducing hardy invertebrates.

By introducing hardy invertebrates first the aquarist will gain experience in acclimatisation techniques as well as stocking techniques. At the very start when the aquarist’s knowledge is low for want of a better word it is probably fair to say that a fair amount of tinkering will be employed. What I mean by this is that the aquarists hands will be in the aquarium a lot moving various corals around as well as the relevant water movement devices until they are satisfied that the conditions provided in the aquarium are suitable for the aquarium inhabitants.

If the decision is made to introduce invertebrates prior to fish then the aquarium, as with fish must be ready for the introduction of them. By this I mean that the nitrogen cycle has completed, there are no large algae outbreaks evident or they are under control and the water conditions are maintained in accordance with the recommended levels. For examples nitrates should be low as should phosphate levels. More than that the water conditions should not just be maintained they should be stable.

With the aquarist deciding to introduce invertebrates in the first instance the equipment purchased and installed should be capable of support the life in the aquarium. For example the lighting needs to be correct. This may sound basic but I hear of a lot of people trying to keep corals under lighting which to be honest is just not suitable for them.

At this point – actually a lot earlier the aquarist should know what corals, fish etc that they want to keep and should have based their purchases around this decision. At this point in the aquariums life you would not be looking at introducing an SPS coral like acropora etc as the aquarium is simply not ready for it.

At this point the corals you will be interested in purchasing are the ones which are not too expensive and do not have the colour of the majority of SPS corals. This is not to say that these corals are dull and colourless as they are far from it but when you compare prices you will see what I mean!

Speaking of purchase again I recommend that you build a relationship with a local dealer, another hobbyist or an online area (like Aquarists Online hint hint…) where you can go and ask advice as to what is suitable etc. Building a relationship with others is important as you can use their experience, their knowledge to your advantage o=plus you can learn a lot about the hobby and will hopefully not make expensive mistakes.

When selecting corals you are looking for corals which are suitable for the beginner. When looking you will probably see some exceptionally colourful species. I would probably stay away from these as there are some species which do not contain zooanthellae and require feeding for them to thrive. A good example of this is the sun coral. There are also other colourful ones which are probably for more advanced aquarists or aquarists who have had stable aquariums for a long period of time.

You have to remember that the aquarium is new and the water, rockwork, sand, glass, equipment etc all needs to age. You can always come back to these more colourful corals when your confidence has grown by maintaining a reef aquarium for a number of years.

In my opinion the list below details what I believe to be good ‘starter corals’ and are suitable for first introduction.

  • Button Polyps
  • Xenia
  • Mushrooms
  • Leather Corals
  • Star Polyps

This does not mean that you should not introduce fish. I personally think that an aquarium with just corals in and no fish lacks movement however I think that perhaps more aquarists should introduce invertebrates prior to introducing fish to gain both confidence in themselves as well as giving the aquarium time to settle.

This of course also does not mean that you will not get problems when introducing fish at a later stage. You might but just remember to acclimatise them properly and use a quarantine tank.


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7 Comments
  1. Hey guys, good article here. This is a topic I don’t see covered too often so it was nice to hear your take. I agree … I would start with an invert myself.

    jeffry r. johnstons last blog post..New this Week, 9/22/08

  2. Its been a long time coming but public opinion has finally changed for the better and I’m glad that its no longer acceptable to not provide the very basic care for your fish.

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