G'day all! Just joined up and thought I'd ask a question about my tiger oscar, Oliver.

I put him in his tank and he's been OK except for a few things.. He doesn't swim around much. Just sits on the bottom and near the filter, sitting still.. He will move around more when it gets dark.

I feed him oscar pellets and the odd cockroach/mealworm/mealworm beetle/spider.. but here's the thing. He seems to only eat stuff that sinks and goes past his eye line.. He snaps them up very eagerly (and judging by the disappearance of four neons that used to live in the tank his feeding response is fine).

The problem is, he doesn't go for stuff floating on the surface at all. Some of the pellets float, and beetles and spiders etc get stuck in the surface tension and float about.. but he doesn't snap them up. He will look at them, and sometimes even follow them around.. but doesn't go for them. I assume he eventually eats them as they're not there anymore, but why is he so timid to eat from the surface?

He is only about 10cm long or so, is it fear of predation?

if hes new to the tank it could take him a couple of days to adjsut to his new home.
as a precautionary thing i would suggest checking your water parameters. at 10 cm he is probably producing more waste the the four neons you had in there before him. if you dont own a testing kit i would recommend getting one. it can save you time in diagnosing problems before they get to serious.

in addition to necro's input.... i would like to ask the following:
how long have your tank been set up? tank size? filter type and capacity?
since you said rookie question... i assume your tank is newly set up.
aside from new tank syndrome, if your tank is not yet properly cycled,
this would be normal and dangerous to your fish......

giving input to those question will help us help you....
btw.... welcome to the site....

The tank has been running for months - my old crayfish inhabited it, until it crawled out and killed itself... The tank is not big enough for a big oscar, but he has plenty of space so far and water is going well. Filter type is just a simple sponge suckered onto the side. This Friday I finish uni at 11 so will be going to a good aquarium store to look at a 250-300L tank and stand, canister filter etc.

PhilK wrote:

now, i can only give theoretical opinion......
your o become stationery or motionless to conserve energy...not only because of new tank syndrome .... but due to poor water condition.... clear clean water by appearance is not an assurance that you do not have ammonia, nitrite, nitrate, and unstable pH in your tank. a simple sponge suckered in the side is not good enough. if the flow rate or turn over is not sufficient, and if you have limited size of media for good bacteria colonies, there is no way for you to attain good water condition.

i am sorry if i give unfavorable comment but that is the way i see your situation.

No such thing as unfavourable comment mate I'm here to learn.
I performed a 90% water change about 5 days before the oscar was put into the tank... plus a clean of the sponge etc etc... would your opinion still be likely?

Just letting you all know tomorrow I will be going to the aquarium store and looking for a 300L tank and a good canister filter to go with it.

well, 300L is almost 78 US gal size.
good luck for your aquarium shopping.

PAUL wrote:

Is 78 US gallons suitable for one oscar, a bristlenose catfish and a large snail?

i am not sure how fast the catfish grows but for oscar
yes,,,, 78 gals with adequate filtration is good enough.
my only concern about the snail is that... my oscar
smashed it on the glass and broke all the shell into pieces.
i hope it wont happen to your snail...

The catfish won't get too big. I think it's almost maximum size already... Just wanted to make sure that'll be fine for the oscar's whole life.

What are the ideal measurements for the tank? I want it to be deep enough for the fish, and also wide enough so they can turn around.

usually, it depends on the space where you gonna
put it.... the depth range of 21" to 24 is good,
while height and length at you choice.