Tilapia will eat fathead minnows if there is little else available. This I know from sad experience...
I would think anything that below a relative size (don't know that length) is on the menu in addition to algea, plants, and detritus. Amazing creatures indeed. Of interest ... Swingle found that the Moz. Tilapia was more vulnerable to hook and line methods than other tilapia he studied. Can't remember the relative amounts but I do remember that more than 500 lbs/acre was harvest by hook and line in one test. This tendency toward invertebrates and as you witnessed even fish probably has something to do with their (Moz Tilapia) hook and line vulnerability.
A diet that includes inverts and small fish would mean that to some extent they overlap the BG's niche. This in part may be why BG seem to benefit from their presence. By benefit, I mean, tend to not be so overpopulated.
