It is a 29g tank with and the pleco was very small and probably no bigger than 3 inches and I have a 150 watt heater, dormant aponogeton plants which I movod out of the tank, 2 peguin 125 bio wheel filters, feed a variety of commercial prepared foods, and I have flourescent lighting. I usually dropped 3 algae tablets in the tank before going to bed when the lights were out and the tablets were all gone by next morning but my fish do eat some of the tablets. I do think his stomach was sunken in. I was going to trade him for a bristlenose pleco. I usually put the algae tabs in around 12:00 o'clock.