of feeding timers (dry feeds).
A significant proportion of the food can be lost to
the protein skimmer. Some solutions exist for this problem. These are either shutting down the skimmer several
times a day during feeding, or using plankton-saving filtration methods.
The first alternative has downsides such as a decrease
in water quality, temporary drops in pH and oxygen levels and skimmers failing to start up without the help of
an aquarist. Plankton-saving filtration methods however
can be promising replacements for protein skimming.
Using algal turf scrubbers, macroalgae-filled refugia and
anaerobic bioreactors instead of skimmers has proven to
be useful in keeping water quality in check.
New filtration substrate now hitting the US mar-
ket are the so-called bio-pellets or “solid vodka,” which
are carbon sources that encourage the growth of ben-
eficial bacteria and have been seen by European aquar-
ists to reduce nitrate and phosphate levels significantly.
These pellets or beads are biodegradable and are rapidly
colonized by aerobic bacteria. Through a process called
immobilization (effectively bacterial colonization and
consumption), this organic substrate is converted into
bacteria which consequently reduces nitrate and phos-
phate. It can therefore be regarded as a sort of “solid
vodka method.” (Both Two Little Fishies and Brightwell
Aquatics are sources of these pellets.) In the end, the
key to maintaining filter-feeding and suspension-feeding
animals, including corals, is providing lots of food par-
ticles for a part of the day, whilst ensuring high water
quality, providing, of course, that the corals in question
eat such small bacterial particulates, which not all corals
do (Coma, et al., 2004; Ribes, et al, 1998; 1999; Gori, et
Corals truly are remarkable creatures, having found diverse ways to take up nutrients. Photosynthates, plankton and dissolved molecules are all part of a coral’s diet.
In terms of plankton-feeding habits, coral taxa can be
divided into two main groups. Stony corals and gorgonians in general are carnivores, whereas soft corals seem
to be mainly feeding on phytoplankton, making them
Corals have many relatives that have not been discussed here, such as the sea anemones (Actiniaria), tube