One of the first graders' father fancies himself a decent aquarist, and offered to maintain a tank in the classroom. The students really didn't care at first, and did not pay very much attention to the twenty-gallon tank placed on a counter in the back of the room. The addition of four very small fish that were somewhat bluish in color with faint black stripes captured the children's attention for a few days, but the novelty soon wore off. Nemo, Dory and the two other tank mates were only about a centimeter long when they were placed in their new home.
Nemo grew much more quickly than the other fish in the tank. He became quite aggressive and killed the smallest of the four. A few platies were added as dither and target fish. A few pieces of bogwood planted with Anubias species were also added to the tank. The additions relieved some of Nemo's pressure on the remaining two fish, and all of them continued to grow.
Nemo, Dory and the third wheel continued to grow. After four months Nemo was 5 cm long, and the other two were about 3 cm long. Nemo and Dory staked out a space behind a piece of bogwood and cleared the sand away. The aquarist-father removed the third fish for her safety and let the platies take the brunt of the beatings that would surely ensue.
All of this activity in the aquarium finally captured the attention of the students in the class. This is the point where Nemo and Dory actually got their names. Every day the students would look in on their pets. The aquarist-father (who also happens to be a science teacher in the school) provided the first grade teacher with a water-testing meter and some chemical test kits to let the kids test the water with. They checked the water daily and recorded the following parameters (averaged for a period of two weeks):
pH = 7.2
TDS = 175 ppm
Temp = 26 C
KH = 2
Nitrites, nitrates and ammonia = 0
The children took turns feeding Nemo and Dory a diet of sinking cichlid pellet, vegetable flake and earthworm flake foods. The aquarist-father-teacher would stop by the room each afternoon to check on the pair and feed them a mixture of live baby brine a frozen bloodworm. The protein-enriched diet soon had Dory looking very plump, and both fish showing a bight blue color and dark black stripes. A small spawning pot was placed into the tank.
The children were told to watch carefully for the day when Dory would be hard to see, or not come out to eat. The kids also observed the pair 'dancing' for each other in full color, cleaning the spawning cave and frequent lip-locking between the pair. (This behavior made sense to the students… after all, their parents kissed a lot too…) The conditioning process only took a week before Dory laid her first clutch of eggs.
Nemo and Dory's first attempt at raising a family was not successful. The students were disappointed, but the aquarist-father-teacher assured the children that a young pair of fish's first attempt is often unsuccessful. The students began their vigil all over again. They were rewarded a week later with clutch number two.
The second spawning met with more success. When the eggs hatched the parents let the wigglers rest in the bottom of the spawning pot for two days, and then moved the brood to a pit in the gravel behind the bogwood. The fry became free swimming on the fifth day. When the fry appeared in a small cloud around their parents, the students sent a representative to the aquarist-father-teacher to get him to come see the babies… 'and come quick!'
The fry were fed microworms for three days, and then were started on a mixture of microworms and baby brine shrimp. They fry were a pearlescent white in color, and stayed together in a tight group. Nemo and Dory were good parents, but after a few days the number of fry started to decrease. There were no remaining fry on the tenth day after they became free swimming. The students were very upset, but the aquarist-father-teacher told them that in nature most of the baby fish that are born do not survive. He also told them that Nemo and Dory were still not the best parents they would be, and that the next spawn would be better.
The children resumed watching, testing and feeding. They were rewarded about three weeks later when Dory deposited a huge plaque of eggs on the inside of the spawning pot. She laid more eggs the third attempt than she did in the previous two clutches. The same rearing process was more successful this time around, and the fry were very active, healthy and fast growing after three weeks.
That is when Nemo showed his TRUE colors…
Nemo had apparently decided that he could raise his huge brood of young better as a single father, and he did his best to eject Dory from the aquarium. A student representative ran with tears in her eyes to get the aquarist-father-teacher. The children learned that sometimes a fish that is protecting fry would see any other fish as a threat, and that Nemo is just trying to do his best to raise his babies. The aquarist-father-teacher removed Dory and the dither platies from the ravages of Nemo's wrath. Nemo continued to raise the fry very well by himself.
The children were given the choice of having Nemo and Dory as a pair in their tank or having some of the pair's offspring to watch grow up. They chose to keep some of the babies. Nemo and Dory were reunited in a larger tank where they have prospered and produced several more clutches. There are ten aquariums in the school and all of them have at least a few Cryptoheros nigrofasciatus 'honduran red-point' cichlids.
The children in the first grade classroom are excited because the babies from Nemo and Dory's first successful brood are large enough now that they are getting color and starting to act like cichlids. There is one that is growing faster than the others. The kids have named 'him' Shamoo.
The student's experience with Nemo and Dory have taught them about reproduction, water chemistry, food chains and the joy of keeping an aquarium. Six of the students talked their parents into getting them aquariums, and now Nemo and Dory's offspring are spread all over town.
The original fish were obtained from Jeff Rapps. A Cryptoheros species was specifically chosen for this project because of their ease of maintenance and spawning, as well as their aggressive and interesting behavior. I have maintained many aquariums in classrooms (currently there are eight in my own room). Cichlids are the best choice. Students find them a lot more interesting than livebearers or gouramies.
An air-driven sponge filter keeps Nemo and Dory's aquarium clean. A 50W heater maintains a 25-27° C temperature. No plants were placed in the tank initially, though the planted bogwood was added later. The tank is positioned about three meters from a south-facing window, which provides enough ambient light to forego an artificial light over the tank. The tank received a partial water change once a week during the period of time when Nemo and Dory were growing up.
© Copyright 2004 Ted Judy, all rights reserved
Judy, Ted. (June 21, 2004). "Nemo and Dory: Cryptoheros nigrofasciatus (Günther, 1867)". Cichlid Room Companion. Retrieved on May 24, 2019, from: https://www.cichlidae.com/article.php?id=305.