Our lab uses the TeT-on system to exert spatial and temporal regulation on the Hedgehog signaling system. We have been having some penetration issues with doxycycline in older fish, so we decided to inject doxycycline into the ventricles to see if we could activate the Tet system. As a test-run, we decided to practice some injections with a fluorescent bead, called Dextran. After several tests with injection needles, dosage and injection sites, we got Dextran into one fish! Hopeful?! This is just step-one of several trial steps to go, but it seems like we are heading in the right direction.