By Don Kinyon
A relatively new addition to the hobby, the tetra Tucanoichthys tucano was described by Gery and Romer in 1997. It’s still not a very common find, almost never in stores and rarely on import lists. They are named for the Tucano Indians that are native to the Amazonas State of Brazil, where the fish are found in blackwater streams of the Uaupes system. With the continued rise in popularity of “nano” tanks, small and unusual tetras such as these are being more and more sought after.
These tetras stay small; not reaching much more than an inch in length. The color of the fish is not extreme, but very attractive nonetheless. The sides of the body sport a distinct dark stripe, starting at the gill and tapering off to the caudle peduncle. The upper body and head are bright gold and the belly is white. There is a pinkish blush at the lower gill. Most of the fins are clear, but in some individuals the gold coloration extends through the top lobe of the tail.
An importer friend had this fish on an availability list and I jumped at the chance to buy some. They were on the pricey end for tetras, but the rareness of the find more than made up for that. The eight specimens arrived healthy and active and were soon searching around their new home, a five-gallon tank, for something to eat. I tried to duplicate the blackwater conditions of the fish’s habitat, so 100% rain water was used and lots of leaf litter and bog wood added to the setup and a clump of java moss covered about half the bottom. The pH was 5.0, TDS of 26ppm, and temperature of 70 to 75°F. The only filtration was a small bubble-up sponge filter. There was no added heater in the tank, so the temperature fluctuated with ambient but the fish didn’t show any ill effects.
The small tetras always seemed to be looking for their next meal, so feeding was not a problem as long as the food was small enough for them to fit into their mouths. I found that mosquito larvae when full grown were too large for the fish to eat, and pupae much too large. Mosquito egg rafts collected from an outside pool and floated onto the tank sufrace gave an almost constant supply of fresh, properly sized live food for the group. These were supplemented with daphnia and newly hatched brine shrimp. The tank had previously been empty of fish residents for some time and there was a population of cyclops crustaceans present. I’m not sure how much nutritional value the tetras received from the tiny animals, but they did seem to enjoy chasing them around.
Water changes were done weekly at around 50% with fresh rain water. The fish always got more active after these, and displayed what seemed (to me) to be courting behavior. One of the males always played the aggressor and chased the other males from one corner of the tank near the filter. I’ve read that these fish will stake out a nesting site and protect it until the eggs hatch, but I can’t say that I witnessed it. The dominant male stayed around his territory unless he was eating and kept all others away. Two of the females were heavy with eggs, by their appearance, but they were chased away with as much vigor as the subdominant males.
On returning home one evening, I noticed one of the females was much thinner. The male that had been guarding his spot was still there, but rather lackadaisical in his patrol duties. Assuming the fish had spawned, I removed the adults to another 5 gallon tank and checked the breeding tank for any signs of eggs. After a thorough search, I found nothing, but didn't really know what the eggs would look like; whether they would be scattered or gathered, brightly colored or clear. A sticky note on the tank with the date the adults were removed reminded me to check on the progress, if any, every so often.
Two nights later, a flashlight check revealed several very tiny fry hanging on the glass near the surface of the water. They were clear, maybe an eighth of an inch in length and looked like tiny shards of glass. They must be very light sensitive, because as soon as the light shone in their vicinity they would dive for the tank bottom. After another day they could be seen free swimming. The fry were too small for even newly hatched brine shrimp, but the moss and filter of the established aquarium provided first food, at least for a few days.
After that, an outside pool was harvested for the fry’s food. A bucket of water from the pond was poured through a standard fine fish net to remove the larger crustaceans and larvae, then through a brine shrimp net to catch the smaller animals. The net could be dumped directly into the fry tank. I’m not exactly sure what the food was, but a cloud of microfood came from the net every time, which was usually every second day, and the fry always had full bellies.
The young tetras grew steadily on this diet and in three weeks they were around three-eighths of an inch long and showed some very nice color. At this point they could easily take newly hatched brine shrimp. The immature Tucanoichthys tucano display a brilliant blue-green iridescent stripe just above the lateral line. A group of them together is quite a light show. It’s a shame, but in a few more weeks the line disappears and the fish acquire the adult coloration.
This spawn produced only eight fish, but all grew to adult with no problems. Later spawns using the same method averaged around ten fish each, which isn’t what you’d expect from a tetra. This tetra, in this hobbyist’s opinion, is worth the extra work. At this writing the adults and some of the young are ready to be passed on to other breeders and a few of the young are set up in a breeding tank with hopes of a more abundant outcome!