Hey fishboy - I was just looking at an old post of yours, and looked at your signature, including the list of fish in your signature. Do you still have all those fish in a 26g tank? If so, you are WAY overstocked, and some of your fish will end up big enough to eat the others - especially the red tail shark, and maybe the pleco. A good rule of thumb is one inch of fish per gallon of water. Check out aqadvisor.com - you can enter your tank, your filter, and your fish - how many of each kind - and the site will tell you if some of your fish aren't compatible, if the size of your fish doesn't fit your tank, if you are overstocked or need more filtration, and how much water you need to change how frequently to keep your fish healthy.