Hemigrammus rodwayi

This article should be titled “The Fish That Never Was.”  This is a very interesting story. First, let me describe this beautiful fish. The Golden Tetra appears as if it was made of metal and does appear as if it was really made of gold. Both sexes look the same with a black spot at the base of the tail and the dorsal and anal fins are edged in white. This species was first described by Durbin in 1909 and was first imported into the hobby in 1930. It is found in Guyana and the lower Amazon. As I started to research this fish in order to spawn it, I was puzzled by the fact that every photo I saw of this species the fish appeared somewhat different. It was described as being difficult to breed and then I read that the offspring do not look like their parents! Further confusion came from a description of this fish by Shultz and Axelrod as H. armstrongi, which referred to a 1955 issue of Tropical Fish Magazine. When I mentioned all of this confusion to my wife, Sandy, she suggested that I check her collection of old Tropical Fish magazines in our library. Sure enough, the magazine was there. However lending even more confusion to this story was the cover of the magazine which was marked as the January-February 1954 issue, while the text inside dated it to 1955!

The explanation is fascinating. The fish we usually see as the Golden Tetra are all wild caught specimens. In the wild, this fish secretes a substance that protects itself against a parasite. This parasite cannot infest this fish in the home aquarium, as it requires an intermediate host for it to survive. Therefore the offspring cannot get the parasite and do indeed look different from their parents. Although thought to be a different species as H. armstrongi, some of these fish are now defined as the H. armstrongi variant of H. rodwayi! There does appear to be some differences in how this fish looks, which is probably based on different local populations.

I found this species not difficult to breed. I set up a pair in a ten-gallon tank over marbles at 79 degrees in water that had been in the tank for about a week. The water was soft and slightly acid. The male started to dance for the female by moving his body in a deep rippling motion. She appeared interested and they spawned the next morning. I feed my breeding tetras baby brine shrimp while they are in the spawning tank, and I left them until the weekend, which was five days later when I observed free-swimming fry. I removed the parents and started my usual feeding of liquid food and baby brine shrimp. After a month, I moved the fry to larger quarters and found there were over 160 of them! Although the babies do not look like their parents, they are an attractive fish. At three months they appear a transparent silver overall, with a black spot at the base of the tail and an intense gold spot above and below the black tail spot. They also have an intense metallic line that follows their lateral line. Under a broad-spectrum light, this line appears gold, yet under a pink type aquarium bulb this line appears greenish blue. The dorsal and anal fins are also edged in white.

The Golden Tetra, in whatever color form, is an ideal community fish. At a little over two inches it is large enough to take care of itself against some of its tougher neighbors, yet it is harmless to itself and other members of the aquarium. It is very active, and loves to swim in a circular motion into the fast moving water from the filter discharge. They do better in groups. I would keep at least six, but ten to twelve in a school is a sight that would beautify any aquarium.

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