There are many types of anemonefish, all of which live in association with host anemones. Some of the cuter, more charismatic species are often referred to as clownfish...like the false clown anemonefish (Amphiprion ocellaris) portrayed in the movie Finding Nemo.
All anemonefish, irrespective of whether they're deemed movie-worthy or not, lay large clutches of eggs near their host anemones. The fish care for their offspring with remarkable devotion and energy by clearing away garbage, circulating water over the eggs, and fending off potential aggressors...until the young fry hatch and swim away.
There are many excellent photographs of anemonefish taking care of their eggs, but somehow, a single image doesn't quite convey the vigour with which these fish attend to their next generation.
During my recent trip to the Lembeh Strait, I spent some quality time with one particular group of saddleback anemonefish (Amphiprion polymnus) at a dive site called Retak Larry.
The fish were in a nice, shallow location with minimal visual clutter. I took several hundred consecutive images of them tending their eggs, and assembled the photos into a couple of time-lapse sequences.
In this first sequence above, the eggs are to the right side of the frame. The bright orange colouration of the eggs indicates that they were laid not too long before I took these images. As the eggs mature, they gradually become transparent, with the nutrients represented by the orange colour morphing into eyes, gills, other vital organs and such.
Watch the video clip, and you'll get a better idea of how dedicated these fish are. There are two large, mature fish that take care of the eggs, as well as a number of smaller individuals swimming around the anemone.
The second sequence below shows a different angle of the same group of anemonefish, with the bright orange eggs in the foreground.