The first AP pulverizers (AP-2) IDAH made was to make eel fish and it was in 1975. Eel feeds float and can be made in extrudate or powder form. Below shows a standard process to make eel feeds in powder form.
Standard process for eel feeds in powder form
Eel feeds in extrude form can be made on extruders.
Crab and Abalone
Crab and abalone feeds are made by pellet mills and they share similar aquatic pelleting process line. The appearances are only different from the sizes (controlled by holes on pellet dies).
Standard process of aquatic feeds pelleting
Abalone feeds can also be made on extruders.
Frog feeds are made on extruders and process shows below.
Standard process of aquatic feeds extrusion