Cliona viridis is oviparous, that is to say the eggs are fertilised internally, sperm being drawn into the interior of the sponge with the incoming water flow. The eggs are then ejected into the water column via the outgoing water stream. There is some degree of synchronisation of the reproductive process as a larval bloom was observed to take place in June during a study undertaken in the Mediterranean. The larvae are planktonic and have limited dispersal ability. When they settle on the seabed they develop into juvenile sponges in about two weeks. Zooxanthellae are already present at metamorphosis, having probably been transmitted during maturation of the oocytes.
