Nannostomus marginatus - Dwarf
Pencilfish
By Brian A. LaNeve - August 2009
Some precautions should be taken when feeding this fish because it seems to be nervous. I on the other hand did not notice this to be true. But I did keep them in a heavily planted tank with no other tank mates.
Sexing - Adult males are more slender than the females. This is especially easy to notice when both sexes are conditioned for spawning. Also the males will have red fins. When not in spawning condition the red in the males fins will vary from either a reddish tint to almost no red at all. My Setup - I used a bare bottom two & a half gallon tank with a glass lid. A well seasoned sponge filter, a heater set to 80 degrees and several clumps of java moss and some floating alflasjslajff and duck weed. For lighting I used an over head shop light mounted about 9 inches above the tank. I only turned on the light for a brief period everyday. From 4pm to 8pm each day. I preformed weekly water changes of just a half gallon of distilled water that I preheated to 78 degrees. I placed the fish in the tank and feed them a diet of live black worms once a day in the evenings. At first I would chop the worms up using a razor blade. After the fish obtained some size I just feed them the worms whole. Placing maybe between 6 to 8 worms in the tank and then doing the same about 15 minutes later. Making sure not to over feed. I did this every evening just around 5pm. Spawning - It was when I noticed that the fish could eat the entire black worm with little to no difficultly that I also noticed that 3 of the fish now had a much brighter red color. They seemed to dance next to each other in a downward position making their already bright color bodies and fins even more stunning. I started to increase water changes now 1/2 gallon of preheated distilled water to every other day. Along with longer light and more feedings. I now started to feed the fish with the live black worms at 3pm and again at 5pm. Also now turning on the light at 3pm as well. It was on the 4th day I noticed the males doing their dance more often. Almost non stop. After about an hour I noticed that only one male was now visible thru all the plants. Upon looking more closely at the tank I could now see the male nudging at the females side and then darting into the plants. This went on for what seemed like an hour or so before the female started to follow him into the plants. The only time the two would stop this behavior is for the male to chase the other males away. He never got overly aggressive towards the other males or the female. This behavior all started around 5pm to 6pm in the evening. After the lights had been on for a few hours. It was when I was going to feed them that I first noticed it, so I did not feed them their second meal this day. The pair of fish continued to do this for several hours. Unfortunately for me I at the time did not have a spare tank to move the adult fish to. Ok, so what I did next was to setup 4 identical setups. Follow the above instructions, but this time in 3 of the tanks I place a plastic screen. I purchased at a craft store. This screen looks like the material that is used in egg tumblers for those of you that use them. I cut the screen to fit the length of the tanks, and left it long enough on the width to go from the plastic rim on one side to the other side making a U shape. Under the screen I place a couple alder cones (Thanks to Eric Bodrock) to not only protect from fungus but to also help keep the screen off the bottom of the tank. I place all four fish in the tank that did not have the screen placed on the bottom and conditioned them for a week. After a week I move the female and the most aggressive male to another tank. I fed them very lightly while in this tank once a day with a good flake food. I left the fish in this tank for 2 days and then moved them to the next setup. I repeated this until the pair was back in the original tank with the other 2 males. Once the pair was removed from the tank I covered the tank with a towel to keep out the light. Starting with the day I removed the adults I started to add 2 turkey baster full of green water 3 times a day to the spawning tanks. On the second day after removing the adults along with the green water I also put in 5 drops of Wardleys liquid fry food twice a day. Starting on the 5th day I stopped the green water and replaced it with micro worms 3 times a day. By the 7th day I stopped the liquid fry food and replaced it with freshly hatched brine shrimp. I continued to feed these two foods (micro worms, baby brine shrimp) until the fry could eat HBH First Bites. To make sure that all fry were eating I fed the HBH powder and the baby brine shrimp for a couple days. Remember there is a lot of food going into this tank, so I would once a day pull out my trusted turkey baster and take out anything sitting on the bottom of the tank. I always placed this water in a clean white bottom cup and let it sit for 30 minutes or so. Sure enough I would always find a fry or two in the cup. I have found this little fish very rewarding and although some work is required it was fun to try something new. I think sometimes us cichlid lovers take for granted the amount of time and care that the parents put in to assure the survival of their offspring.