Hi all, I just bought my first oscar today, and I'm kind of concerned now. I'm not positive of my tanks size in gallons, nor any other size, but it is 14" wide, 7" long and 12" deep. It is fully filtered (carbon,foam and that white stuff) and is heated to about 26 degrees (celsius) constant. Now, the fish is only about 3 inches long right now, so he fits like a glove with the tank, but I've been reading that I need a big tank for the guy, as they grow lots. So my first question is, when should I get a new tank, and how big?

Also, today, for his first day I fed him 3 guppies, he swallowed them all whole after chasing them for a bit, but now hes just kind of acting sluggish? He's still a bit active, but he just kind of hides, and sometimes floats on the bottom, kind of at an angle... is this normal? Or are these just new pet fears . So, second question, should I keep on feeding him guppies till he gets big enough for goldfish? Or is it not wise to only feed him live food? I know the fish are good, as I buy them from a trusted source in my town here, a small little petshop that breeds their own feeders!

So, there you have it... Im a little concerned, but my betta acted the same way when I got him new (Save for chasing feeders around the tank ). Well, that's all, expect me back lots!

Well, now according to my calculations it's only a tiny 10gallon tank! Help?

Okay, 10 gallons is far too small for one Oscar. Obviously your Oscar is very small and but when it grows bigger, you will have problems in a tank that size. The picture below is a 6 inch Oscar in a 20 gallon hospital tank. You can see that even this small Oscar looks big in this tank, I dread to think what a tank and tank would be like



Don't give your Oscar feeders all the time, maybe once or twice a week. If your pet shops sell live insects like cricket, get them. Also get some good quality pellets. Vary the diet, that's the key to keeping an Oscar healthy.

Oscar sometimes do sit funny. They will often sit on the bottom the tank lying to one side. They will often do this if they have been upset in anyway. Sometimes after a water change, they will often sit in the corner lying to one side. I think it's their way of telling us that they are not happy with what you have been doing in their home. However, they shouldn't do it for very long. If a fish swims funny, sits to one side for long periods of time, you must investigate a little more, swim bladder disorders can often make fish do this. If after a water change, a fish starts swimming funny, it can be because of dramatic changes in temperature. Just keep an eye on the Oscar. I've never had it myself, it's just something I know of.

Your oscar is fine in that tank for the moment. However I would start to think about getting a bigger tank now. Oscars grow really quick. Buy the time you have decided which tank, then got it and then cycled it, your oscar will be getting to big for your tank.

As for the size of the new tank bigger is better, 55 gallons being the accepted mininum size for one oscar but opinion is changing to 75 as the minimum

So I could meet halfway and go with a 60 gallon then? I have somewhat of a limited budget... how much would a tank that size cost me? Is there packages with all the necessary equipment (bigger heater, bigger filter)? Should I buy used tanks as well?

60 gallons would be okay for one Oscar. See how much you've got to spend, try and find the cheapest tank available. Don't go for one that is more than let's say five years old. Try and buy a quite a young tank. Get yourself a reasonable heater, I would say 200 W would suffice. Make sure it's fairly robust. Again, get some adequate lighting, no need to get anything special. Now, the filtration is a different ball game altogether. This is where getting rubbish is a big no-no. Don't buy the first filter you see. Get one that is rated quite a bit higher than your tank. You are better off getting an external canister filter that you can pack lots of biological media inside. The more biological media you can get in it, the better your water conditions will be. Don't worry too much about the mechanical filtration, I don't like taking up too much room with this, as long as you've got a piece of sponge, you'll be okay. You may just have too clean and it every couple of weeks. You want the little ceramic balls, they are really good in these canister filters. Either them, or the stuff that looks like pasta.

The two most important things when keeping Oscars is an adequate tank, and the filtration. You really can't have too much filtration.

Thanks for all the help! Well, payday is friday and there is tons of garage sales to be found. Although I'm sure Petland has some 55 gallon tanks for under 200 dollars (canadian). Ill get the best filter I can, assuming its not overly expensive... and my heater is rated at 150w, is that ok?

150 Watts will be perfectly okay. I am only using 300 W on my 125 gallon tank and the water is around 27°C. Oscars are okay down to around 21°C. What you've got to remember with heating is it best to have a heater that corresponds to the amount of water you've got. Maybe even a little more. Even though a heater that is rated at less than your tank does the job, it means it'll be on all the time. That will cost you more money. If you have something that is rated a little more, it will only come on when it needs to. That's my theory anyway

When you are looking for a tank you have to think about the dimensions. An adult oscar is usually about 12 inches long, so you need a tank with a front to back distance of at least 18 inches. I would go with 18 inches height too. My personal opinion is that these are the minimum distances for a adult oscar. If you go with a 4 foot tank this would give you a volume of about 67 US gallons/56 UK gallons