Page 54 - Encyclopedia of Aquarium and Pond Fish, 3rd Edition

52 FRESHWATER FISH: MAINTENANCE

tank decor. Reducing the length of time that the aquarium nitrite poisoning when this chemical is present in concentrations
lights are on will help to curb this problem, as will making of just 0.5 mg/liter, whereas most other fish will be unaffected
regular partial water changes (which keep the nitrate levels until the level rises to 10–20 mg/liter. Ammonia can be
low) and introducing fish that browse on algae. removed by the chemical zeolite, which is either added to the
filter (if present) or simply dropped into the water.
Monitoring water quality
Test kits and meters (see p.46) should be used to make weekly
checks on the water quality. Daily visual checks are also vital;
any unexpected change in the appearance or behavior of your NEW TANK SYNDROME
fish may indicate that there is a problem. For example, if the Water conditions in a new tank take time to stabilize. There is an
gills of a fish become brown instead of the normal pink, it is initial rise in the level of ammonia, which the fish excrete as waste.
likely that there is too much nitrite in the water. This will As the biological filter starts to work, beneficial bacteria break down
interfere with the ability of red blood cells to carry oxygen. the ammonia into slightly less harmful nitrite, which is eventually
Regular partial water changes will usually cure nitrate excess. converted into nitrate. Although this is called new tank syndrome, a
similar situation can arise in a mature tank if the filter’s efficiency is
A rise in the level of nitrite or toxic ammonia may be due to dramatically reduced. This could be caused by the use of antibiotics
“new tank syndrome” (see right), caused by overfeeding on a (which will kill the bacteria), a breakdown in the oxygenation of the
regular basis (see p.49), or a result of overstocking the tank, filter bed, which is essential for the survival of these aerobic
which places extra demands on the filtration system. microbes, or simply the replacement of the filter sponge.
Fish differ in their susceptibilities to dissolved chemicals,
which is often a reflection of their habitat in 11 The rapid initial
peaks of ammonia
the wild. Those occurring in fast-flowing 10 9 and nitrite in a new
water where there is little opportunity 8 tank are followed by
a slower climb in the
for pollutants to accumulate, such as 7 nitrate level. It takes
discus (see pp.142–143), are much more Level (mg/liter) 6 5 about seven weeks
for a biological
vulnerable than those that naturally inhabit 4 filter to become
small ponds. Discus show obvious signs of 3 fully functional.
2 Ammonia Nitrite
1 Nitrate
0
0 4 8 12 16 20 24 28 32 36 40 44 48
Time (days)

The stocking density of the tank has
a direct impact on the efficiency of
the filter. The larger the number VACATION ISSUES
of fish, the more difficult it will be
for the filter to deal with their • Arrange for a friend or
accumulated waste (see p.30 neighbor to check the tank
for more on stocking densities). every day in case there is a
power failure or any of the
equipment malfunctions.
• If someone else is to feed
the fish, show them exactly
how much food they should
give each time in order to
prevent overfeeding.
• As an alternative, consider
using an automatic feeder
or a food block.
• Carry out a partial water
change and check all the
equipment before you leave.
• Leave a contact number
in case of emergencies.

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