I got a bn pleco about a week or 2 ago now and its the first pleco ive kept, i have all the necessary requirements needed for it but hes not eating any food i offer him like blanched zucchini, cucumber, peas, algae wafers since i got him however hes really active during the day eating off the glass and filter. He also has a black belly which i think he had when i got him, is it normal?