Choosing and Setting up a Marine Aquarium

Livestock

Some hobbyists go for a fish- only aquarium, some like a combined fish- invertebrate aquarium, and although the basic choice of livestock is the same, and indeed most fish from marine outlets these days are suitable for both, there are additional rules for a succesful combined setup, in particular the very popular reef aquarium type.
This chapter is not a long list of species with individual characteristics- such information is widely available. Just be aware that some of this is plagiarised, one book just repeating the information presented elsewhere. So myths about one species tend to be propagated in various books over time, adding to their strength.
Many species are widespread, but may well have local variations in behaviour and food preferences. The fish also haven't read the books.

6.1 Fish

For all setups

The usual reasons for going for a fish- only setup is that you can put in any fish you like, so long as you have: i) inter- fish compatibility

Many fish, even those which shoal in the wild, may not tolerate others of their own kind in a confined aquarium environment, especially if you introduce a second specimen when the first has already established itself. Fish that resemble each other may well not get on, nor may those which share a food source.
In the initial readjustment of the pecking order, a chased fish is a stressed fish and may develop signs of disease the next day, or everything may have settled overnight. In the wild, any fish being attacked can always swim off, in the aquarium it can get as far as the top back corner, if it is still being attacked there, it can only escape by jumping out or by your removing it in time. Or it dies!

Generally, introduce fish to your tank in reverse order of aggressivity. Particularly the advice often given to start up the tank with a couple of territorial damselfish is a big problem.

ii) enough room for larger fish

If you really want to have large angelfish, butterflyfish, triggerfish, surgeonfish or wrasse then look at the body shape and fins- a streamlined Acanthurus lineatus just needs to flap its pectoral fins two or three times and is already at the opposite end of your 2 metre tank. Or do you want to have those fish which out of boredom are only happy when readjusting your decoration?
Food requirements and excrement quantities may also mean you cannot maintain the water quality that many creatures, particularly sessile invertebrates, need to thrive.

iii) capability to care for the individual fish

Acanthurus leucosternon, one of the most beautiful of fish, needs absolutely stable clean water conditions, and tolerates other stress factors badly. This is THE example of a fish which isn't excessively priced, is readily available and if you don't know how to look after it will certainly die within a short time and may get cryptocaryon infections which the other fish then contract and you may lose your whole stock. Many other tangs and surgeons are much easier to keep. The same goes for many other groups of fish. A good dealer will advise you.

Some fish are food specialists (certain butterfly and angelfish)or need to have food available all the time(certain Anthias) or which may need to be alive (sea horses). Some are going to grow too large too soon (hands off shark eggs) or are too dangerous to consider. I have, though I admit not recently, seen Stonefish and Blue ring Octopuses for sale in quite normal shops. The chances of you not making it to hospital after a bite or a sting are quite high. My local shop told me he would never consider stocking such creatures.

For a combined or reef setup

Make sure the fish you purchase don't have your favourite invert as a main constituent of its diet. Not all butterfly and angelfish will eat your corals, not all triggerfish will decimate your shrimp population. Damselfish will be happy with a small area and swim in, out of and round the rocks and corals.
Carpet anemones will catch fish, reef lobsters will hide all day and may catch sleeping fish at night, even if well fed. What does your dealer have together in the show tank?