Tiger Oscar floating on side

Question
I have a Tiger Oscar that is less than a year old, about 4.5" and until today seemed normal and healthy.  This morning when I went to feed him he was lying on his side at the top of the tank.  When I put the food in the tank he didn't respond at first, but when I shut the lid he started to right himself.  He seemed a little slow in righting his self using mostly his front half of his body.  5 minutes later when I went back to the tank he was eating and chasing his tank mate away from the food like normal.  

I've never seen him floating on his side before at the top of the tank so I'm concerned that there may be something wrong.  Is there anything I can do to prevent this from getting worse or should I not be concerned about it?

We feed him twice a day - in the morning he gets flake food or cichlid pellets and in the evening he gets either blood worms or a cricket. Last time the nitrates/ammonia were checked (about a week ago) they were fine and the pH was at 7.2

Answer
Hi Susan:  This question is very difficult to answer because there are so many possibilities and not one clear answer.  Usually when fish float on their sides it can be attributed to either a swim-bladder disorder or an intestinal blockage. Both conditions can affect the fishes buoyancy making it harder for the fish to remain on the bottom of the tank or to swim normally.  Your Oscar may have the beginnings of either syndrome.  Another reason that fish sometimes are found in weird positions can be attributed to tank aggression.  I have had a parrot fish for about five years that spends her day up-side-down laying on the gravel... and everyone who sees her tells me my fish has died but when I open my tank lid she flips over and swims just fine to the top to eat...and then goes back to the bottom to be upside down.  I think she does this because one of her tanks mates will pick on her and even though that tank mate was moved to another tank... she still lays there like a dead fish.  

When I first started reading your post I suspected an intestinal blockage and when I consider all of the clues I go back to a small blockage.... I say this because if it were an aggression issue he would not be the one chasing everyone around during feeding time... it would be him getting chased.  I go back to the fact that he rights himself slowly which could be either caution or his struggle with buoyancy....  I do know that pellets are very dry and even though the fish lives in water they can sometimes lead to blockages which is what I think may have happened.  I would feed him nothing but brine shrimp for the next 3-4 days and see if his condition gets any better.  The brine have tiny shells on them that act like roughage and should help him get back to a normal pooping cycle... If you do not see any improvement in the next day or so let me know and we can approach this from another angle.... dave