Nice, a big GF!
Honestly I do not know the actual answer of how often. But I know it was mentioned as sparingly. Gf need a good amount of fiber for good digestion and tha amount of sugar in fruit, which doesn't usually have much fiber and also usually has too much sugar, and would generally be too high for a good regular diet.
In nature, GF wouldn't eat much fruit. But I bet they would eat it if it was in the water, lol!
Also not absolutely positive but I think especially easy with melon like honey dew and cantaloupe. I'm deciding again whether to keep a GF aquarium or pond. A friend of mine is keeping my GF in their pond for now. So I would also like to know this for sure!
New to FW fish? First tank in a long time or EVER??? Need some info on keeping fish?
Start here - Aquarium Advice Article
FW Favorites right now Clown Loaches, any shrimp - SW Vase Red Mangroves