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.
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.
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.
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.
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?