Back to the fish. In our plankton net tows, we see lots of different fish! Some are larger and some are smaller, but they are all small enough to get caught in a slow-moving plankton net. We also saw a mahi-mahi, or “dolphin” fish. This fish is called a dolphin, but has nothing to do with the mammal dolphins. This fish was about three feet long, and was brilliantly colored. People also sometimes call these fish “dorado”, which means gold in spanish, because they are brilliant yellow, green and turquoise.