Blackspot Climbing Perch (Ctenopoma intermedium)
This Blackspot Climbing Perch species is quite unique. It is equipped with a “suprabranchial” organ which allows it to use atmospheric oxygen in addition to the normal respiratory process. A pair of respiratory organs are situated in chambers in the head above the gills. Each “head lung” consists of a thin plate convoluted into many folds containing numerous blood vessels. Upon taking a mouthful of at the fish dives, forcing air into the chambers where oxygen and carbon dioxide are exchanged.
Growing to an average length of between 55 and 60mm, they are light to dark-brown, paling to light brown towards the belly with between 7 and 9 dark longitudinal bands running down the side and a black spot on the caudal peduncle. Several dark lines radiate outwards from the posterior side of the eye across the gill cover. Breeding males turn much darker. Its body is slender with a short abdomen and a small mouth containing sharp conical teeth.
Occurs in dense marginal vegetation of rivers and lakes, lagoons and channels of swamps and floodplains. Prefers shallow, calm waters.
Although rare, has been found in the Upper and Lower Zambezi. More common in the Okavango,
Kafue and shire rivers. Also occurs in Lake Malawi and coastal swamps near Beira in Mozambique and St Lucia Bay in Natal, South Africa.
Predates mainly on aquatic insect larvae, mayflies and caddis flies and on terrestrial invertebrates.
Males build a nest of bubbles at the waters surface under which spawning takes place. The eggs float and are stowed in the nest and guarded by the male.