that they loosely band together while foraging. We often suggest buying a half dozen Corys, tetras, Danios or Rasbora, because those are schooling fishes and that seems to meet a need for company. That may even have health benefits. In nature shoaling and schooling have an advantage in terms of protection.
Indeed there is a study which indicated that predators following a school of fish, in that case, wouldn't attack the school. But when a member of the school strayed behind and stood out as different, whammo! Grim way to deal with dropouts!
So your guppy may be looking for other guppies. A couple of neat Guppylog posts have recorded the seeming delight guppies exhibit when new guppies arrive.
Or, as suggested, he may be one of those energetic teenagers. ;) In either case he may be mildly neutrotic, but he'll get over it. :)
All the best!
uncle scott
[ Parent ]