Angel fish and Discus prefer to eat crustaceans including shrimps. Therefore, Srhimps added to the aquarium for algal removal will most likely be eaten by these fishes. In view of this fact, Otocinclus and Siamese Algae Eater should be selected as an algae-eater, but these Cichlid members are big eaters and prefer highly-nutritious feeds which may cause eutrophic aquarium water and promote algal growth.
To avoid deterioration in water quality, it is necessary to keep Cichlid in Nature Aquarium having a larger volume of water and equipped with a highly efficient filtration system. It is also a good idea to plant the aquatic plants that absorb nutrients vigorously such as Echinodorus family plants to control the eutrophication; or to use cosmetic sand in the foreground location to make the maintenance easier and secure a wider swimming space for fishes.
As for layout, it is recommended to avoid very complicated layout taking long-term maintenance into consideration. A layout featuring dynamic arrangement of epiphytic plants and rosette-type plants such as Echinodorus and Cryptocoryne is suitable for these fishes.
If you wish to make the above tank with Iwagumi Layout type it is advisable for you to put about approx 6-7 Dozens (80 Nos) Neon tetra or Cardinal tetra into an aquarium to have an attractive aquascape.
This number can be changed depending on the size of the fish. These fish go very well with an lwagumi layout and a school of these fish can make the viewers feel the natural flow and movement in the aquascape. To achieve this effect, a relatively large number of fish need to be added to the aquarium because they do not swim in unison if only a small number of them are put in the aquarium. Small-sized fish that usually swim in a school or shoal in nature appear to be more stable if many of them swim together in an adequately sized tank, rather than having only a small number of them.
In the case where a new aquarium was set up using brand-new filter media, fish should be added after three to four weeks when the environment within the tank is stabilized and aquatic plants grow almost up to the water’s surface. If an existing filter media already colonized with bacteria is used, it is possible to add fish to the aquarium when ammonia is no longer generated, i.e., about one week after the setup, as long as no algae is observed in the tank.
It is advised to add fish in about two phases, since the balanced self-purification process within the tank can be affected by adding a large number of fish at the same time. You might want to add fish as soon as possible once the planted aquarium is done, but it is, for the sake of fish, better for you to wait until the environment is adequately stabilized (i.e., the condition in which water is clear and sparkling, no algal growth is observed and aquatic plants grow lush and healthy).
Keep in mind that overpopulation of fish must be avoided to prevent growth of algae. Adding a relatively small number of fish and feeding easily digestible and absorb-able food such as Micro Pellets are a key to maintaining a beautiful planted aquarium.