I don't have any experience with mixing other genera with darts, but it is sometimes done in very large habitats with species from the same wild habitat that require nearly identical conditions. While you are researching this, I would recommend getting some personal experience with darts of your choice first. While another type of animal might not intimidate or interfere with one species or morph of a dart frog, another might not tolerate it. I think it is very important to be totally familiar with both animals before mixing them together in the same tank.
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Patty
Pahsimeroi, Idaho

Dendrobates: auratus blue, auratus Ancon Hill, tinctorius azureus, leucomelas. Phyllobates: vittatus, terribilis, lugubris. Epipedobates: anthonyi tricolor pasaje. Ranitomeya fantastica, imitator, reticulata. Adelphobates castaneoticus, galactonotus. Oophagia pumilio Bastimentos. (updated systematic nomenclature)