I have a huge red-bellied piranha that weighs about a pound and a half. is about 9 inches long, and fatter then a desert plate!. anyways my question is why wont he eat? he hasn't aten in over a month, just sitting in the same corner, day after day after day. I drop shrimp so it lands and hits him on the nose..nothing..the shrimp lies there till it rots and I have to take it out. I drop a wriggling dew worm infront of his nose...nothing...my other juvenile piranhas come rushing in and destroy the worm. this big one doesn't eat he is becoming frustratingly boring!. I do weekly water changes of 25-30%, siphoning out the gravel as im going along. I use easylife easy start, as well as another brand of nitrifying bacteria, I use either prime, or API water conditioner to make it safe depending on my mood that day lol, I use nutrafin waste control to break down organic waste and help to clean my filters. the fish are in a 90 gallon tank for now. will be moving all 5 to a 125 soon. my ammonia and nitrite lvls are ZERO, my nitrate are very low, water temp fluctuates in this heat of the summer but since the weather is turning into fall gradually here, the tank is back around 79-80F. I just cant figure out why this big piranha doesn't do anything besides sit in the same corner day after day after day. and never eating.