Kandrona rays are the Yeerks' primary source of sustenance. They feed by absorbing them through their skin. Kandrona rays are beamed through a Kandrona ray/particle generators into the Yeerk pool, or on the Yeerk homeworld from the natural sun. Later it was revealed that the Iskoort also feed off of Kandrona rays. Yeerks and Iskoorts need to feed off of Kandrona rays every three days.
|Andalite technology||Dome Ship | Escafil Device | Hirac delest | Mirrorwave call | Z-space transponder | Morphing | Mag-Hover Truck | Quantum Virus | Shredder | Gleet Bio-Filter|
|Yeerk Technology||Anti-morphing ray | Dracon beam | Gleet Bio-Filter | Kandrona | Kandrona Rays | Nova-class Empire Ship | Pool ship | Blade ship | Mag-Lev Train | Hunter-Killer Robot | Yeerk Pool | Bug fighter|
|Ketran Technology||Explorer | Time Matrix | Fire-And-Forget Explosive Homer | Uninet | Adge|
|Other||Dropshaft | Ixcila (Arn) | Pemalite crystal | Skrit Na Saucer | Hawjabran Colony Ship | Hawjabran Freighter|