CichlidFish.com - Fish That Think.

My boyfriend and I have had this Oscar for a little over a year. We have him in a 30 gallon tank, getting ready to move him to a 50 gallon. We had a glass thermometer in his tank, well he didn't like it so he rammed into it and broke it. He likes to try to move his heater out of the tank. I noticed the other day him swimming into the side of the tank. He also jumped out of the water, hitting the lid. Is this normal, & does anyone know why he does this.

When my Oscars catch a glimpse of themselves in the glass, they will chase it and run into the glass.

Mine have also broken a heater. I have found out, if the Oscar's don't like something, they will fix it to their liking.

Mine have hit the lid many times. But I have 4. If they get in an argument, they hit the lid, and everything else in the tank.

It's an Oscar thing, mine lives in a 180g with fish he can dominate.  He has set up an area which is his 'bedroom' and if anythin comes into it ... it gets it.  Now this can be a moss ball, his golf ball or the heater if it takes his fancy (or the gravel vac).  I have noticed the larger the tank, the larger his area becomes (was in a 115g before).

I only use an external thermometer with large cichlids and use extra support for heaters to stop them being broken.  I have heard of O's being bored as well, so some fake plants may well distract him (O toys) if he has no tank mates.  The best thing if keeping an O though is to get the biggest tank you can afford to upkeep for him.  As said above my O is in a 180g (he shares his bed with a Torpedo Barb - I was surprised !!) and has a shoal of Rainbowfish following him around.

Another note tho, yu say you've had him for a year, he must be pretty big now which must also be driving him crazy with limited roomk, he must be at least 8" ?

The tank is too small. Thats why he hits the wall. Swimming up and down against the wall is also usually a sign of this or of stress. Moving stuff around in the tank is because he's an oscar.

Something similar happened to my O last night.
Around 1:00am I was in bed working on going to sleep when I heard some sloshing/thumping noises coming form my O tank. twent to check it out and here he was swimming around, but there was some stuff floating around in the water. I turned on the tank light and saw that the stuff in the water was fish scales; my O had bashed his head/dorsal fin on the tank cover. So now there are big scrapes on the top of his head and a little damage to his dorsal fin. He had flipped out once before because I spooked him one night, but he has never been hurt like this before. Is there anything I can do make sure it doesn’t happen again?  Do i need to do any Oscar first aid or anything...or will his scrapes be ok?
I have him in a 55gal tank by himself and conditions are good. There was nothing in the room moving around or anything.

How big is he? If he is big, then he probably flipped out because a 55 gallon is way too small. When mine were in a 55 gallon, until they were about 6 inches, they did things like that all the time. They fought constantly, hit the lid, killed all my plants and my decorations. As soon as I got them into a bigger tank (150 gallons), they were so happy and never did anything like that again.

My Oscar got his fin torn pretty bad once. As long as he was in the 55 gallon, he did not heal. I think because he was unhappy. As soon as I got him into his bigger home, he healed pretty fast. I did not medicate him.

I would say he is about 5 1/2 inches, so I think putting him in a 150gal by himself would be a bit of an over kill….unless I find him a buddy.  He has always seemed happy to me, he eats good. Likes to swim around and greet me when I get home. He hasn’t tried to take anything in the tank apart….he played with the thermometer a little when it came unstuck and was drifting in a corner. But this is the 1st time I have seen any abnormal behavior. But i will be keeping a closer eye on him.

Your right, a 150 gallon is a lot. I wouldn't put 1 O in anything less than a 90 gallon.

Sometimes O's get into moods. They are unpredictable. They do weird things for weird reasons, and a lot of times there is no explainations.

I would definitely just keep an eye on him. O's are little weirdo's.

O's are little weirdo's.

No, they're BIG weirdos!!

Very true! 

As I posted above my O shares a 180g with a variety of other fish, but he too has banged head on the lid, most notably when he 'thinks' there is a fly or something that he can get to that is on the lid.

I have 2 oscars.....one is in a 70 gallon and one is in a 150.....Oscar is in the 150 and he always "BIG FISH"'s me when I feed him, loves to bang his head on the lid......my other Oscar, Scarface, dosent "BIG FISH" but he swims FAST from one side to the other and constantly moves his rocks around......and both of my O's do the "swim against the side of the tank because I am tough" thing........Oscars have a tremendous personality and love stuff to screw with.....I dont even set the tanks up with cool toys anymore, I just let Oscar and Scarface put stuff where THEY want it.......and Oscar is in his tank with a HUGE plecostimous and a gourami as well as a catfish from Wal MArt and he hasnt messed with any of them....well Plec is a foot long and the 2 of them go at it when Oscar is feeling moody, but all in all I got happy fish!!