You notice a 110L (29gal) tank. At the top you see a large bunch of anacharis floating under a single fluorescent tube. As you look down to the bottom, you note that the back and sides are covered with algae. You see a power filter hanging on the back and a small sponge filter bubbling in the corner. The bottom is covered with a thin layer of gravel. A large piece of driftwood divides the tank into two parts. To one side of the driftwood you notice a large pile of lava rocks. Three pink variety Archocentrus nigrofasciatus (convicts) about 5cm (2in) long are swimming near the rocks. Two have brilliant gold flecks over much of their sides. Drawing on your knowledge of convicts, you surmise they are females. The third convict has no gold flecks, but it does have a long, pointed dorsal fin and a small hump on its forehead. This is the male. The male and the larger female are busy moving gravel by the side of a lava rock. The male occasionally displays to the female. You recognize this as pre-spawning activity. The other female hovers nearby. You wonder why she doesn't move away from the pair to the other end of the tank.
You turn your attention to the other end. A large pile of various rocks is all you see at first. The smaller female follows you. Suddenly, another convict darts out of the rocks and chases the female back to the lava rocks. As this new convict swims back to the rocks, you notice pale gold flecks on its sides. Ah, another female you muse. You look closer at the rocks and notice small, pink bodies swimming in the rocks, convict fry. You estimate there are at least a dozen young fry. You lean in for a closer look and the mother swims protectively to the glass. You notice that the rocks are covered with algae and the fry are grazing amoungst it. You wonder about the fry and the tank conditions. You look around and see a log book to the side of the tank.
The first page of the log book contains water quality information. You see that the tank is maintained at a pH of 7.0 and a temperature of 25C (78F). The tank is fully cycled with the ammonia and nitrite both at 0 ppm. Every two weeks 25% of the water is changed. You see that the hardness is a little soft at 8GH.
The rest of the log book details the spawning and growth of the fry. You see that this is the first spawn for these fish. You read that, about 6 weeks ago, the male and female starting locking jaws in a mating ritual. The next day around 40 eggs were laid in the corner of the tank on a cleared off portion of the glass. The log says that at first both parents guarded the eggs, but the day after laying the eggs the female chased the male off. By the third day, the eggs had hatched. At this point, the power filter was turned off and an established sponge filter was added. 6 days after hatching the fry became fully free swimming. The log shows that, at this point, Melissa started feeding the fry. The fry were fed a combination of liquid fry food, powdered fry food, frozen daphina and, of course, whatever they could find in the abundance of algae. For the first two weeks, the fry were fed at least 5 times a day. You note that the dry food was suspended in water and the daphina thawed before being fed to the fry. After the first two weeks, the fry were fed 3-4 times a day. You notice that recently Melissa has found a supply of brine shrimp eggs so live nauplii have become a regular addition to the fry's diet. The logs notes that as the fry got larger the mother started protecting more of the tank. Observing the tank now, you estimate that the mother and fry have complete control of almost 2/3 of the tank. Although several fry were lost in the first few weeks, you see that none have been lost in the past week. You also note that a sponge was added to cover the intake of the power filter and the filter was turned back on at low speed two weeks ago.
You wonder what the adults are fed. As if in answer, Melissa comes over with a food container in hand. She tells you that they are mainly fed flake food and pellet food. She also gives them frozen bloodworms a few nights a week. She tells you they also get live brine shrimp nauplii every afternoon when the fry are given nauplii. She tells you the mother takes her fair share of the fry food and the others try to but get chased off. She says they also get the occasional snail when her other tanks overrun with snails.
You take one final look at the convict family. The fry dart in and out of the rocks while the female stands guard. You leave with the memory of the fish fresh in your mind.