Hole in the head temperment

Question
I have an Oscar that is just about 2 years old and has started developing hole in the head at a rather rapid rate.  He is a work fish and if I am not here he does tend to get neglected.  I have started doing more water changes and I have tried to vary his diet but he will only eat pellets now.  He is about 8 inches long and is in a 20 gallon tank.  have you heard of any side affects of the hole in the head such as twitching and aggressiveness?  Way back in the day Chief (because he used to run the show around here) would jump for his food (he loved tubifex worms), then as he stopped eating live food he also stopped jumping.  Now he can't seem to eat enough and will lunge out of the water as soon as I open the lid.  I now have a heavy duty stapler on the lid and just feed him through the opening in the back by the filter.  He actually nipped a co-worker the other day.  Yesterday I was just kinda sitting here watching him and it looked like he was twitching.  I do not want him to suffer.  Does the disease actaully cause pain?

Answer
Hi Dawn,
 There are several things going on here that are unrelated.
First, the hole in the head.  Hole in the head is a symptom and there is still a lot of debate about what actually causes it but the bottom line is this: you need to do more water changes and that will hold it in check.  A large oscar in a 20 gallon tank is pushing it, and he is going to require changing about 25% of his water EVERY week.  It is far better to change 25% every week than say 50% every two weeks.

  Can you possibly get him a larger tank?

  The aggression and twitching are related but have nothing to do with the hole in the head.  They have to do with the fact that he is maturing and is getting highly territorial as is the normal thing for oscars.  The twitching is part of his signalling system and depending on the context can mean things like "back off, this is my space" although in other contexts it is used to court females.  So he is definitely not suffering.  In fact, it sounds like he is doing quite well except for the hole in the head.  

  One more thing about the aggression.  Just because he is aggressive about his space doesn't mean he is turning nasty. In fact, oscars get VERY attached to their people and get very depressed if their people go away.  (He can easily tell one person from another.)  So don't misinterpret his aggression to mean that he doesn't like you; he just wants you to know that the 20 gallons is his.

-- Ron
  rcoleman@cichlidresearch.com
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