Disguised as motionless floating leaves, South American leaf fish (Monocirrhus polyacanthus) are amazing camouflage artists. These small, predatory fish rarely spawn in captivity, but Academy biologists have found success with this delicate breeding process. To our knowledge, no other institution has successfully raised them from egg to adult, but we are well on our way, with a new group of hatchlings and a couple of 11 month-old juveniles.

In order to encourage the adults to spawn, the biologists did what they could to recreate the conditions at the onset of the rainy-season in the Amazon, when dissolved substances are diluted. That means making incremental adjustments to the tank’s water chemistry with very pure, acidic (pH=3.0), slightly cool, peat-filtered water. The low barometric pressure associated with San Francisco’s winter rains may also have been a factor. The recently-hatched fry at the Academy are now behind the scenes, so biologists can better manage their care and photo-document their development. You can check out the adults in the “Staff Picks” area of the aquarium.