Many words are used on this page that may not be familiar to someone who is not normally associated with the anatomy of an embryo. Here is a list of these words and their simplified meanings.
Day 1

On Day 1, we predicted that our Medaka egg was 29 hours old by comparing it with other pictures of Medaka in the reading guides from our classroom. This would mean that it was in the 19th stage, "Blastopore". The Vitelline Viens were clearly visible, and the yolk took up most of the egg's interior. The fish's body was not yet developed, and no body parts could be seen. Since it was on the 19th stage, we predicted that by Day 6, it would be hatched. By then it would be in the thirties in reference to stages, and this is the time when Medaka eggs tend to hatch.

Day 2

On Day Two, not much of the fish's interior had changed, except that the texture of the egg was more prominent. The focus point of the egg was still the yolk. Just like the previous day, no fish could be seen, but the egg seemed to be becoming more focused.

Day 3

On Day Three, the egg had really begun to change significantly. Though the yolk was still present, it was not simply a huge circle in the middle of the egg, but more of a fill-in inbetween all of the other organs that were now developing. The tail had begun to stretch across the length of the egg, dividing it in two, and in the upper left corner, the head was beginning to form. The rest of the egg had not changed, except that the cytoplasm that had once been surrounding the yolk was now dwindling, as the fish was growing.

Day 4

On the fourth day, we began counting heartbeats, since our Medaka's heart had begun to pump blood. The heart rate that ours had was 86 beats per minute. The eyes were clearly seen for the first time. Also, if observed closely, we could also see the movement of veins throughout the fish's body. This meant that the heart was finally in full use and was pumping blood to the body of the fish. Starting on this day, the blood can be seen in the fish as a pinkish tint in the egg. Some can be seen near the eyes.

Day 5

On day Five, the eyes were clearly visible and darker than day four, and we counted 154 heartbeats per minute. Although not much of the egg was as focused, the Vitelline Veins could be seen as becoming thicker and shorter in length, and the fish's body was obviously growing in size. The blood was also becoming more visible.

Day 6

On Day Six, our Medaka had a heartrate of 127 beats per minute, and the fish had a clear anatomy. Its eyes were dark and seen on the right of the egg. The tail, or spine, could be found curling throughout the perimeter of the egg. The Veins on the outside of the egg were now more sparse and less dense. Although we had predicted Baby Pompey's early hatching on this day, he was not quite ready. Since this day was a Friday, we predicted that he would hatch over the weekend, since he was in the advanced stages that meant hatching would come soon.

Finally. on Day 7, Baby Pompey hatched!

It took awhile to capture a picture of the difficult baby fish, but eventually we got one. Now its body can stretch to its full length, and its gills can open up and be used. He will soon grow to be an adult fish.

Baby Pompey!!