Acute axonal degeneration (AAD) and Wallerian degeneration are observed in the zebrafish posterior lateral line (pLL) nerve after laser axotomy. A three dpf larva, injected with HuC::GFP to image and axotomize a single pLL neuron. (a) Intact neuron with a typical bipolar morphology. White arrowhead shows central projection, yellow arrowhead shows peripheral projection, and square shows cell body. (b) Zero hours postaxotomy (hpa), arrowhead points to position of laser axotomy. (c) Thirty minutes after axotomy. AAD was complete: arrowheads indicate extent of AAD. (d) Three hours after axotomy, the distal axon began to fragment (arrowheads). (e) Four hours after axotomy, some fragments remained. (f) Five hours postaxotomy, clearance of debris was almost complete. Scale bar, 100 μm.