we've got a bit of a problem with our oscar, he's been fit as a fiddle until yesterday when he went off his food, nothing unusual about that, he does it once every six weeks,and then eats again,but when i came back from work today and approached the tank he took off and hid, when i took a closer look he was what i can only describe as petrified, desperate to get away. Every evening he usually sits at the side of the tank next to my chair looking at me, now he sits behind the bogwood looking miserable. The oscar in question is only five inches long (no idea how old) and he has an oscar chum at four inches long who is fine, tankmates to the oscars are, two dwarf snakeheads, a whiptail cat (small), a pleco (five inches). The tank is a fluval 240l, excellent filtration and the water quality is excellent (30% re-min RO water change every week). The fish in the tank all get on really well. I am sure this is not just the oscar being sulky.

Have you checked your water quality? Please post results just to rule out a water problem. But O's often sulk, As long as you know for sure that all is right with your water quality I wouldn't worry too much.

nitrate is less than 10mg per litre, nitrite is less than 0.3mg per litre, ammonia is zero, PH is 7.5-8.0, thanks for responding

I think if I were you I would do a 30% water change now. your Ammonia and your nitrite should always be 0. your nitrate can be safely up to 40 ppm but at that point you should do a water change.

Oh by the way WELCOME!!!

thank you

You are very welcome!

welcome to the site.

how long the tank had been set up?
no kids around who may tapped the glass?
the way you describe your o shows he had been
poke. pleco may also cause such changes in mode

thanks for responding dude. The tank has been set up for five months, and there are no kids about tank tapping. Curious to know, what is 'poke' and how could my pleco affect his mood, pleco can get a bit stroppy when an oscar blocks his path but they've been together from the start. Good news is he's cheered up (a bit), but still not 100%. I got a bit worried yesterday because i thought he was going to be another statistic of irresponsible breeding which seems to have risen in the last twenty years due to the increasing popularity of the fish, i'm not going to rant now cos i've just got back from work and i'm beat

when you put your hand in the tank and your trust or stroke
your hand toward the fish, that is poking, and it will make
your fish swim away. pleco could anchor his sucking mouth to
the body of your sleeping oscar... and sometimes can bore a
wound or pull out the intestines. it will result to splashing
or darting at night night.

Oh i understand now,oscar is back to his old self, which is cool, i have kept these fish for a number of years and the only other fish not to take any crap from my oscars have been pleco's (tough buggers) so it's possible you're right. I'll keep an eye out for any shennanigans, thanks Paul.