Sucker Fish - Cannot keep them alive

Question
I keep a tank of "Parrot Fish" which are very healthy and growing beautifully and I have bought 7 sucker fish (one at a time)  to keep the tank and glass clean but we  have lost everyone. They seem to be quite happy and feeding the tank temp is about 26oc with filter and air. But it is so  strange that they are healthy one minute and gone the next. Do you think the Parrot fish (I think they are chiclids) are murdering them? Pleae advise as we are fairly new to having fish

Answer
Hello Sarah,
It could be possible that the Parrot Fish are attacking them. Cichlids are usually aggressive, Parrot Fish included, and will attack anything that gets into their territory.
Think of it this way, fish have their "bubbles" just like we do. We need our own certain amount of space, and some of us don't like people to intrude on our space. Sometimes even acting aggressive. Your parrot cichlids have a certain amount of territory they need, and if their tank isn't big enough, they will not tolerate other fish coming into their territory.
So keep that in mind.
As a side note- don't forget that Plecostomus (your so called suckerfish) grow over two feet long, and can very easily intrude into other fish's territory.
They are also strictly plant eaters, and if there is no visible algae in your tank they may just be starving to death.
You can feed them algae wafers, steamed Zucchini, and cucumbers.