Cichlid Room Companion


Is This Nanochromis dimidiatus?

By , 2001. printer
Kurt Zadnik, 2002

Classification: Taxonomy and phylogeny, Africa.

(This article was originally published in Cichlid News Magazine, Jan-96 pp. 12-15, It is reproduced here with the permission of author Kurt Zadnik and Aquatic promotions).
Nanochromis sp. 'silverbelly' An adult male Nanochromis sp. "SilverBelly". Photos by Kurt Zadnik.

In my early days as a dwarf enthusiast, I spent hours in the local library pouring over old tropical fish magazines and ancient reference books. One I finally bought for myself (and cherished) was J6rg Vierke's Dwarf Cichlids (1979). You wouldn't believe the time I invested reading this book from cover to cover over and over again. I still recall dreaming that I'd acquire some of the incredible fishes pictured in those pages. One that I couldn't wait to get my hands on was Nanochromis dimidiatus. The illustration in Vierke's book shows a bright red male displaying for a female? an incredible sight. I now realize that there must have been a number of other people lusting after the same fish, because invariably after presenting my slide lecture on dwarf cichlids, an oldtimer will walk up to me and say, "Do you ever see that little red dwarf anywhere?" The fact of the matter is that Nanochromis dimidiatus has not been in the aquarium trade for almost thirty years.

Before Pierre Brichard was forced out of Kinshasa (Zaire) in the early 60s by political unrest, he exported N. dimidiatus on a regular basis. In fact because of its beautiful coloration, it was very popular, and wild fish were as readily available as the common krib (Pelvicachromis pulcher). However, N. dimidiatus proved to be more difficult to raise and spawn than kribs, so once import of the former ceased, it quickly disappeared from the hobby. Over the years interest in N. dimidiatus was kept alive solely by those who had once kept it and those who had seen its photographs.

Finally in 1985 Heiko Bleher gathered available information about collecting localities for N. dimidiatus and returned to Zaire to collect it himself. His full story (Bleher 1987a; 1987b; 1987c) is recounted in Tropical Fish Hobbyist and I recommend it to anyone interested in tales of "bringing them back alive" as only Heiko can relate. The bottom line for us here is that Bleher located at least five different color forms of a Nanochromis species; the jury is still out today as to whether or not any of them represents the original Nanochromis dimidiatus. I remember reading about his exploits, which renewed my interests in obtaining this wonderful fish. Incredibly at about the same time, a friend who regularly imported fish from Germany offered to get me a few pairs. Although the price was rather high, I decided that I couldn't pass up the chance.

After receiving the fish which Horst Linke (1979) had dubbed the "Silverbelly Nanochromis" or Nanochromis sp. from Kasangani (Zaire), I set them up as pairs in 20 gal show tanks with very soft water treated with blackwater tonic, lots of live plants, sponge filtration, and a choice of several spawning structures. The thing that first impressed me about the fish was not their coloration but their size. Although obviously adults, they were the smallest dwarf cichlids I had ever kept. Males were just over 1.5" total length, while females measure barely 1.0" TL. The base color of the male was brownish-gold with a faint black stripe running the length of the body along the lateral line. Other than a hint of gold in the breast area and rows of faint red and blue spots in the unpaired fins, he was quite plain. The female showed a little more color with a similar ground color and a solid chocolate-brown stripe along the lateral line. Below the stripe she was almost white with a patch of shiny scales over the middle of the ventrum (hence the name "silverbelly"). Edged in gold and white, her unpaired fins were transparent save for a touch of red in the posterior soft dorsal. Her most attractive markings were the bright red coloration surrounding the mouth and a patch just above the orbit, looking as though she had applied lipstick and eye shadow.

Nanochromis sp. 'silverbelly'
Nanochromis sp. 'silverbelly'
Nanochromis sp. 'silverbelly'
Nanochromis sp. 'silverbelly'

Upper left: A sexually-quiscent male Nanochromis sp. "silverbelly"; Upper right: A sexually-quiscent female Nanochromis sp. "silverbelly"; Lower left: An adult female Nanochromis sp. "silverbelly" in breeding colors; Lower right: A post spawning female Nanochromis sp. "silverbelly". Photos by Kurt Zadnik.

I conditioned the sample gradually by feeding them a smorgasbord of live foods, including baby brine shrimp, adult brine, black worms (only a few), and daphnia, as well as flake food. I tried to simulate the water conditions of their natural habitats? pH 5.5-6.0 with no hardness? but achieving zero hardness is extremely difficult even if you are blessed with soft water. I performed weekly 20% water changes, using water run through a reverse?osmosis unit with added trace elements and blackwater tonic.

After a month of such TLC the pair went through an incredible color change. The male's head became a bright reddish-orange color which extended posteriorly over the body although fading somewhat near the tail. His unpaired fins were covered with narrow vertical rows of alternating bright red and blue spots. The borders of the dorsal and caudal fins were edged in bright orange and white. The female, whose belly looked as though it would burst at any moment, also had a bright red-orange head but her body had turned a shiny silvery color with a pastel pinkish cast to it.

Topped off with a shiny gold blaze over her back, she made quite an unusual sight. I was still amazed at the small size of the fish, which had grown very little since I had received them. The pair courted in typical dwarf cichlid fashion with the female performing an "Scurve" dance in front of the male, flaunting her swollen belly; the male responded with rapid quivering and tail-slapping. The female eventually chose an upturned terra cotta pot (4" in diameter) as a spawning cave. I did not expand the drainage hole in the bottom of the pot (as I usually do for larger dwarfs) and before spawning the female could barely wriggle through it.

Following an extended courtship, the female finally spawned. Afterwards she looked like a deflated balloon! I was not surprised at her appearance when I saw the number of incredibly large eggs that she had spawned. The 70 or so eggs were each almost 0.1" long and suspended from thin threads from the top and sides of the cave. Although the first spawning did not produce fry, subsequent spawns hatched in about three days at 80° F. Unlike other dwarf cichlid parents, the female kept the wrigglers in the spawning cave for the entire incubation period. Fry became free-swimming in another week and were nearly 0.25" long when first herded around the tank by the parents. They spent a lot of time picking food off plants and seemed to especially like to graze on Java Moss, Vescicularia dubyana. The fry were large enough upon emergence to accept baby brine shrimp, micro?worms, and finely crushed flake foods as their first meal. Fed properly and provided with frequent water changes, the fry grew to maturity in 9-12 months.

Unfortunately (for reasons explained below) I was never able to produce enough fry to distribute them to other hobbyists. Since that original importation in 1987 I have never again seen the fish offered in the U.S. They still show up infrequently on German lists, but the prices are so astronomical that I assume German aquarists are also having a very difficult time maintaining the fish.

I learned a lot during the months that I pampered my "silverbellies." While I was keeping them I continually attempted to manipulate pH using phosphoric acid. I would add acid until the pH dropped to the desired level and then measure it again the next night. Invariably the pH would be back up to where it had been before adding acid, so I'd repeat the process. Since I didn't understand the role of buffering compounds at the time, I didn't realize the roller coaster ride I was taking the fish on each time I added acid. I now assume that I eventually did the fish in as a result of my obsession with trying to get the water down to the "right" pH levels. I now realize the dangers of adding acid if you don't know exactly what you're doing; personally I have totally abandoned such an approach. Instead I've found that if you replace old tank water frequently with reverse-osmosis treated water with added water conditioners (e.g., small quantities of trace elements and blackwater tonic), the acidity of the water will reach an equilibrium within the range you're trying to achieve. In other words, "don't worry, be happy!" Sparkling clear soft water and live foods are the most important ingredients to success.

Whether or not Nanochromis sp. from Kasangani is the same as my old favorite Nanochromis dimidiatus is, in the long run, unimportant. What is important is the enjoyment of dwarf cichlids (or cichlids in general) and the sharing of experiences with other interested aquarists. Isn't that why we all got involved in the hobby in the first place?


  • Bleher, Heiko; 1987a; The search for Nanochromis dimidiatus, Part I Kasuku. Tropical Fish Hobbyist 36(1):54-73.
  • Bleher, Heiko; 1987b. The search for Nanochromis dimidiatus, Part II The upper Zaire. TFH 36(2):32-47.
  • Bleher, Heiko; 1987c; The search for Nanochromis dimidiatus. Part III Equator. TFH 36(3):46-67.
  • Linke, H.; 1989; The Silver-bellied Nanochromis. TFH 38(1):102-111.
  • Vierke, J.; 1979; Dwarf Cichlids. T.F.H. Publications, Neptune, NJ.


Zadnik, Kurt. (August 19, 2001). "Is This Nanochromis dimidiatus?". Cichlid Room Companion. Retrieved on December 16, 2018, from: