Your pic looks very similar to young ones I saw in the cenotes of Riviera Maya.
The ones I saw (young and old)were constantly grazing on algae that grew very lush in sun drenched areas (some more than a few inches long), seemed to be the major part on their diet.
The water was also fairly brackish.
I will definitely pick up that Nat Geo
She eats Repashy soilent green as well as NLS Thera A pellets so I know she is eating well. She's healthy in every other way, just very slow growing. I never expected to see such slow growth on these guys, it's very interesting. At the same time I'm comforted knowing I'm not the only one with slow growing WC dempseys

