I'm not sure what your definition of "very good" water parameters is, what is the temperature, pH, KH, GH, NH3, NO2, NO3?
Apart from the high protein content Tabimin pellets are too small and fall apart shortly after. This isn't helpful for pleco's that's why they have pleco tablets or Plecomin those stay hard in water.
However even that shouldn't be the staple, feed them vegetables, blanched or cooked. They love squash, zucchini, broccoli and stuff like that. They are not picky and eat all the time so he isn't feeling well.
Apart from the high protein content Tabimin pellets are too small and fall apart shortly after. This isn't helpful for pleco's that's why they have pleco tablets or Plecomin those stay hard in water.
However even that shouldn't be the staple, feed them vegetables, blanched or cooked. They love squash, zucchini, broccoli and stuff like that. They are not picky and eat all the time so he isn't feeling well.