What are you using to "spray" under the beds? Did your vet recommend it or is it something else? Don't let Tigger anywhere near any areas you spray.
Fleas live on the host, meaning the pet. So, hopefully, your vet double-checked before applying the Advantage. In any case, keep an eye on Tigger, comb through his fur for evidence of remaining fleas, and do NOT apply any further shampoos, or any other application of Advantage...Advantage and Frontline can only be applied once every 30 days. Fleas can indeed survive in the environment if both pets are not effectively treated, and/or if the environment isn't treated (vacuuming on a daily basis, bedding washed, etc). With Athena going outside, she can continue to bring them back in, but hopefully, the Frontline will take care of that.
Tiny black bugs
Re: Tiny black bugs
..........Traci