Yes you can offer the flies to the chameleons. The flies wont live very long (their lifespan is typically three or four days -just long enough to mate, lay eggs and die). They get their nutrients from their maggot / larval stage. Phoenix worms (the larva of the Black Soldier Fly) eat excriment / manure, rotting flesh and rotting vegetation. They are voracious maggots that will consume anything from a spoiled potato to chicken guts in a remarkably short time. This makes them pretty easy to keep, if somewhat gross. Depending on how much they're fed, they can go from egg to maturity in as little as two weeks or as long as six months.
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Sandra
BC Canada