IANA entomologist, either, but I’ve smashed plenty of fruit flies in my kitchen (and other places around the house :mad: ), and yeah, looks like a fruit fly to me. Size of a pencil lead, goofy look on its face, no brains at all, zooms around in small, random circles going “What? What?” when you disturb it–yep, that’s it.
I understand that reptile owners have a word for fruit flies: “Snack”.
IOW, no, there’s no danger to your beastie from the bugs. If he can catch one, it’s just more protein. The biggest danger is that they’ll breed in the cricket tub and out-compete your crickets for their food (that’s what they’re eating, BTW, as well as any other organic material they happen upon), and your crickets’ breeding rate will drop.
No to mention moving on from the cricket tub to the rest of your house, “new worlds to conquer” and all that…
“An easy way to get rid of them”? Yeah, get rid of the cricket tub. “An easy way to get rid of them without negatively impacting the crickets”? No.
The only way to get rid of fruit flies without nuking your house and moving to a new city is total, absolute, 100% cleanliness. They will eat, and will breed on, and in, anything organic–wet dishrags, the sink drain, a dirty spoon left on the kitchen counter for more than a day. You have to keep after them. You’ll have to keep the cricket tub scrupulously clean, and squash any flies you see, every chance you get. If it was me, I’d get a duplicate cricket tub, and move the crickets back and forth from Tub A to Tub B (freshly scrubbed) every morning.
Survivors from the cricket tub purge will migrate to other places in your house, so you must be vigilant. And after about a week or two of ruthlessly squashing any and all survivors, you’ll be bug-free.
Good luck with it. I think fruit fly threads comprise about 25% of all General Questions threads.