Different species of poison arrow frogs can be caged together if you pick the correct species and set up the enclosure correctly. Pick species of similar temperaments to be sure they do not overcompete or harass each other. I also recommend choosing frogs from different niche environments. For example, choose a social terrestrial species and a social arboreal species with similar humidity and temperature requirements to cohabitate in one vivarium. Make sure that the enclosure is large and that you provide plenty of food items for the frogs. Some owners find it fun to design a tank with indigenous plants and with species that cohabitate in the same regions in the wild. I recommend this approach because if the frogs inhabit the same territory in the wild, they are typically suitable to share a habitat in captivity. Ask your breeders about species you’re interested in and whether they can cohabitate.
Other herpetofauna, such as geckos, small chameleons, and lizards, can be housed with poison arrow frogs as long as you provide adequate space and species housed together are nonaggressive toward each other.
Fish are a fun addition to vivariums, but I don’t recommend putting them together with poison arrow frogs. Fish can increase the presence of bacteria and pathogens in the tank, which can have adverse effects on your frogs. Aggressive fish can also nip the frogs or drown them if the frogs fall into the water. Fish can be rewarding pets, but don’t put them in the same aquarium that houses your frogs.