Dottybacks and Reefs
Some aquarists suggest that it is actually detrimental to keep dottybacks, as well as other microcarnivores, in a reef aquarium. They claim that these fish deplete the number of small invertebrate herbivores (e.g., amphipods, copepods) that aid in keeping filamentous algae in check. However, I have had and seen many reef tanks in which microalgae was not a problem, despite the presence of one or more dottybacks. The pseudochromids may compete for natural prey with some of the less agile microcarnivores, such as seahorses, pipefish and dragonets. You may therefore not want to keep them with fish that depend on natural food stocks on live substrate for most of their nutrition.
Assessor Spawning Habits
The blue assessor (Assessor macneilli) is a mouthbrooder. The male member of the pair holds the egg mass in his mouth for about two weeks until they hatch, at which time the fry enter the plankton. Male blue assessors, which are larger on average than females, apparently outnumber females in aggregations and tend several broods over the duration of the mating period. The males cease feeding during the egg-tending phase and are more quick to seek shelter than nonbrooding individuals.
However, fish expert Kevin Gaines has told me that unlike its blue relative, the yellow assessor (Assessor flavissimus) does not orally incubate its eggs. Instead, the eggs are laid in a nest and tended to by the male.
Want to read the full story? Pick up the June 2009 issue of Aquarium Fish International today.