Geophagus proximus
Geophagus proximus is widespread in the headwaters of the Amazon River in northeastern Peru and western Brazil. The fish prefer to stay in clear water, near banks and islands, with a substrate of sand, fine gravel and earth. The water in these areas has a brownish colour due to the presence of dissolved tannins that result from the decomposition of organic matter at the bottom. The fish are relatively uncommon in trade, although even novice aquarists will be able to keep them.
The sex of young fish cannot be determined from their appearance. Sexually mature male Geophagus proximus is usually slightly larger and has a more elongated tail fin than the females. male coloration is brighter, and some of them develop a hump on the back of the head. The body is coloured bluish or yellowish. There is a black spot on the body. The maximum size of the fish is 22.5 cm.
Geophagus proximus is kept in a group of 5 to 8 specimens. Over time, the group will form a hierarchy in which weaker fish are subordinate to the stronger. If the fish are kept in smaller numbers, the weaker individuals may become a target for the dominant specimens.
Since the Geophagus proximus are relatively large fish, they require an aquarium of at least 600 liters. Share the tank with other peace-loving fish of similar size.
Most important in the design of the aquarium is a sandy substrate, because Geophagus proximus feeds by sifting sand through the gills. Coarser substrate such as gravel or fine pebbles can damage the gill filaments and even cause blockage. Large driftwood and large stones can be placed in the aquarium. Low light should preferably last about 10 hours per day.
Water parameters: temperature 24-32° C, hardness dH 1-10°, acidity pH 4,0-7,0. The fish are sensitive to water quality and therefore should not be introduced in an aquarium where biological equilibrium has not yet been established. Powerful filtration using an external canister water filter, aeration and weekly change of ½ of the aquarium water with fresh. In case of poor water quality, the fish become ill and their development slows down considerably.
Under natural conditions, Geophagus proximus eat small aquatic and terrestrial invertebrates, plant seeds, detritus and various sediments on the bottom. Under aquarium conditions they are fed with frozen and live Artemia, Daphnia and chironomid moths. A variety of dry sinking food containing spirulina can also be given to the fish. The fish should be fed 3-4 times a day in small portions.
Reproduction
Geophagus proximus breeding is generally not difficult. Keeping the tank clean and feeding the fish with a variety of quality food will be sufficient for successful spawning.
During the spawning season a temporary pair of producers is formed from a group of fish, although in some cases the pair can exist for quite a long time. The spawners select a spawning spot, which is usually a smooth surface of a large rock.
During spawning, the female hatches about 150-200 eggs, which immediately after being fertilized by the male collects them in his mouth, where the eggs are incubated until hatching. The fry begin to swim at the age of 8-11 days. The parents keep an eye on the fry all the time, chasing them away from other fish, and in case of danger the fry immediately swim into their mother's mouth. The fry spend the night in their mother's mouth for the first time.
The fry are fed with powdered dry food designed for cichlid fry as well as artemia nauplii. In order to keep the stock, it is advisable to transfer the fish fry to another aquarium as soon as it is noticed that they no longer remain in a flock.
The life span of Geophagus proximus in an aquarium is about 15 years.
