The Butterfly Barb: A Rewarding Challenge

Author: Paul Hards and John Robertson

The butterfly barb is a rarely seen species that is challenging to keep. Two skilled fish breeders collaborated on spawning it and offer their tips on how to do so in your own home.

Small but Feisty

The butterfly barb (Barbus hulstaerti) is a colorful and active little fish. One of the smallest barbs, with a maximum size of barely an inch, it has unfortunately been rarely available due to decades of political unrest in its native Congo region, punctuated with occasional internecine war. It is also reputed to be tricky to keep and very difficult to breed. Until recently, I hadn’t seen any alive for 30 years, when a friend had two specimens. They were unhappy, lacked the vibrant colors, and were soon to die.

This little barb with the blunt head, bold blue-black spots, and flashes of yellow in the male’s dorsal and anal fins has remained at the top of my list of target fishes since I saw their stunning photos from the deepest regions of Africa in 1976. It was found to be challenging to keep alive in captivity and came from water with a pH of 4.

Breeding Success

About 18 months ago, Paul Hards obtained 15 specimens from a German source via importer Tom Halvorsen. True to form (at first), nine of that group were dead within a week. But Paul, a skillful fish breeder, had the remaining fish spawning in a few weeks. In a well-planted species tank with a capacity of 10 gallons, with wool mops and a few almond leaves on the bottom, a few of the fry survived.

Do Adults Eat Eggs?

It seems the adults eat any eggs they can find, but they don’t consume the fry, which normally hatch 24 to 48 hours after spawning. For such a small fish, the fry are quite large, and while the parents are shy fish that often keep to dense cover and swim in the lower reaches, the young seek out open spaces and stay close to the surface. Paul feeds his young paramecium and microworms the first few days, but all his small fish, including the adult barbs, get copious amounts of brine shrimp, and the fry get their share of this as well.


The young barbs grow fast and show the first large spot in less than a week. At two weeks, the second spot is distinct, and within six weeks, the young fish have reached ½ inch long and are swimming with the parent group. This has been a straightforward process in Paul’s tanks. Despite their tricky reputation, Paul has reared numerous groups of butterfly barbs over two years, seemingly without difficulty. He does point out that the adults can bully the smaller fish and males are rather rough with the females, so he periodically removes a group of youngsters to other accommodation. He also notes that more males than females (females are distinguished by the lack of color in the fins) are produced among the young.

Water Requirements

Paul keeps these fish in tap water that has stood for several days and been treated with dechlorinator. The pH is about 6.0, and the hardness about 6 dH. Temperature is 72° to 75°F. They don’t seem to like it too hot, and Paul does not change too much water (only 20 percent every couple of weeks).

Not So Easy

In a recent magazine article, Frank Schafer notes that the butterfly barb is one of several similar species that are even less frequently imported (Aqualog News 94). B. hulstaerti, he observes, lays eggs within the substrata, and the eggs have variable hatching periods, much like the eggs of killies. This may be an adaptation to survive occasional droughts in the native streams, but we have not been able to corroborate these observations.

Setting Up the Tank

I received half a dozen of Paul’s first-bred fish about 12 months ago. Two females and four males, they were about three quarters grown and clearly sexable. I tried to follow Paul’s advice as much as possible, setting up a 9-gallon species tank that was heavily planted with Java moss and Indian fern with peat moss and oak leaves scattered across the glass bottom. However, I used rainwater as I do with all my softwater fishes, and it wasn’t long before the dwarf barbs spawned.


I was delighted to see a group of six barb fry and thought I was well on my way to fulfilling my childhood dream. In fact, based on my diary’s records, I know these adults have spawned in my tank at least 12 times. Sometimes just one or two fry survive, on other occasions six or eight, never more. In contrast to Paul, my breeding “success” (for a long time) was that I managed to raise just two fish!

The first two batches were fine until about seven days old, when they began disappearing one at a time. From the third spawning, I rescued two fry at that seven-day stage, and they grew fine in a separate small tank kept at 80°. Of the original adults, three died about six months later, but the two youngsters are now fine with the remaining adults and a further trio of Paul’s homebred fish provided a few months ago.

Feeding Issues

These adult butterfly barbs seem very happy, eating flake food supplemented by baby brine shrimp and grindal worms, yet none of the subsequent fry have ever survived more than a few days. I tried everything I could think of.

I believe most perished because of lack of food. The fry are constantly active and no doubt have a high nutritional demand. Unlike many fry, the butterfly barbs don’t go browsing for several weeks—they stay in the open water near the surface and wait for the plankton to reach them. Paul achieves this with paramecium in the early days, yet despite my best efforts, few have survived past a week or so. In several cases, my fry disappeared when I had to leave for a few days on business or holiday and no particular food was available in the water column. A few fry of almost any other species would find enough microscopic food in a well-planted tank, but these little guys don’t go looking for it.

Back to Basics

I finally went back to the basics and questioned anything I could have been doing wrong. I went away from rainwater and used tap water just as Paul does. Paul and I have similar tap water, but I didn’t notice any difference in the regularity of spawns or the number of fry surviving at first. Then I tried something I should have tried months earlier.

One day after watching the fish spawn, I transferred the adults to a separate tank. Pretty basic, I know, but I had avoided moving the parents before because of their sensitive reputation and because Paul had never found it necessary. Anyway, it worked!

I soon had group of 13 fry that developed okay for a month. Then half disappeared, and I managed to raise half a dozen—not great, but a modest success all the same. I have now passed the adults and young back to Paul to supplement his group.

I think it all goes to prove that you can take good stock and the best advice, but sometimes it is just not enough. I have been keeping and breeding fish for over 40 years, yet even very experienced aquarists can struggle with some fish that refuse to do what we want.

Yet, as Paul has shown, B. hulstaerti can sometimes be easily bred and is certainly a beautiful and charming fish. A group of butterfly barbs makes a striking addition suitable for a community setup with other small softwater fishes or by themselves in a small species tank.

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