Back when I had these little frogs (granted, that was about 10 years ago now!!), I kept a minimum of three and at one point I had 7. If I had to choose, I would get rid of a couple of guppies and replace them with another frog or two.
Once they get more comfortable in their surroundings, he/she will become more active. The fish might make it nervous too. Just a heads up: my ADFs would eventually chase and nip at the beautiful guppy tails when I kept the two species together. Eventually, I just had a small tank with guppies and a small tank with just frogs so that the poor fish would not be stressed. Best of luck to you!