I was just wondering if anyone can come up with a reason for why my plecos die. I have a 55 gallon tank with a neutral ph and no ammonia or nitrite or nitrate. Nobody picks on them. The lights on for about 12 hours a day and i also drop some shrimp pellets which it looks like they nibble on. I had one it died in about a month. Tried another same thing. This time i bought 2 ayt the same time. They lasted for about 5 months. My longest yet. One died about 1 week ago and then the other just last night. What am i doing wrong?? I also have a kinda big irridescent shark that eats the pellets, but im pretty confident i drop enough of them. So can someone please come up with a reason.