4-day-old Zebrafish Embryo Micrograph Image, Wellcome Image Awards 2014

Scanning electron micrograph of a four-day-old zebrafish embryo. To capture this image, the zebrafish was physically attached to a stub (specimen holder) by its tail and tilted to 65 degrees. As zebrafish embryos are approximately 1 cm in length, making the whole embryo too big to be captured in a single image, three separate images had to be taken along its length and then stitched together digitally. Colour was then added to the black-and-white image using tones and shading to try and represent the reflectiveness of fish scales. The zebrafish is a small, tropical, freshwater fish that originally comes from Asia, and is commonly used as a model organism to study developmental biology and neurodegeneration (the deterioration or death of nerve cells) in vertebrates.

Here is a normal-looking image of what the embryo looks like.

Here is what the little guy looks like floating in your freshwater aquarium.  Not so alien-looking now, is it?

The zebrafish is native to the streams of the southeastern Himalayan region and is found in parts of India, Pakistan, Bangladesh, Nepal, and Burma. The species arose in the Ganges region in Eastern India, and commonly inhabits streams, canals, ditches, ponds, and slow-moving or stagnant water bodies, including rice fields.  Zebrafish have been introduced to parts of the United States, presumably by deliberate release or by escape from fish farms.

SOURCE:  Wikipedia