View Full Version : Small or large tank first?

03-15-2007, 12:05 AM
This is just a general question about oscars. Would it be best to start off a pair in a small tank and move them to a larger one as they grow or would it be best to just start them off in a 120 gallon? Thanks!

03-15-2007, 12:20 AM
With oscars, its pretty much go big or go home. 55 for 1, 75 for 2, 100 for three, 120 for four, 150 for 5, etc.

03-15-2007, 12:34 AM
It would be better to just start them in the big one first. If you are wanting a pair start with about 6 and let them pair off. You will need the big tank eventually, you might as well save yourself the cost of a small tank and skip it. The only problem would be what I call big tank syndrome. This is when small fish are very skittish in a big tank. I think they are convinced it is too big to be for them and they must be food for something much bgger already in the tank, but that's my theory. They usually just need time to settle in.

03-15-2007, 12:38 AM
The only problem would be what I call big tank syndrome. This is when small fish are very skittish in a big tank. I think they are convinced it is too big to be for them and they must be food for something much bgger already in the tank, but that's my theory.

lol. Let them gain a false sense of security, THEN you put in the giants!

03-15-2007, 01:10 AM
That's why you need dither fish :)

03-15-2007, 02:04 AM
Whenever you are considering purchasing a fish you know will get large always try to get the tank they will need as adults. We started out with 2 2" oscars in a 90 gallon, boy did they look funny in there, but now they look quite happy. Unless you find something you decide you want and have to bring it home now and are not sure about the requirements, always start with what you need for them as adults. It doesn't take long for an oscar to grow another 3-4" so you will be setting up that big tank long before you expected. The other consideration is that it is said that fish emit hormones into their water that can affect growth and stunt it if they are not in an aquarium that suits them. How true that is I don't know, but I don't know if I would want to risk it.

03-15-2007, 04:06 AM
I've seen too many people say they are going to get a bigger tank when their Os grow a little, and then life happens and the tank becomes a pipedream and the Os begin their long slow painful death from bad water or stunting. You should just bite the bullet and get them their permanent home right away and then no matter what life throws at you, you already have it. They'll soon fill up any size tank you get them, and the water quality is guaranteed to be better the more water there is which is gonna help 'em grow even faster

03-15-2007, 02:24 PM
Many fish emit growth inhibiting hormones, but I can't say for sure that oscars do. However I know angels do and would be surprised if it wasn't true that most if not all cichlids do. The bigger tank only makes it take longer for the hormones to have the same affect, what is most important is the water changes. You can have a 300 gallon tank for one, but eventually the hormone concentration (and other things that inhibit growth and affect health) will build up and take their toll if proper water changes are not carried out.

Lady Hobbs
03-15-2007, 02:43 PM
I totally agree here reptileguy. I believe the tank size does make a difference in their growth rate. I believe that's probably why bala sharks are said to get 12 inches but we seldom see tank raised over 6. Same with loaches and angels.

03-15-2007, 03:06 PM
Oh it does, I am just saying it isn't just that, no water changes in an otherwise big enough tank can be just as bad. I have seen a lot of people put two oscars and other things with them in a 55 and the oscars usually hit about 10", then someone has one in a bigger tank with the same water changes or better, and the thing is 15" or more.

03-16-2007, 12:39 AM
...go with the big tank...add some hiding spaces for when they're little...shouldn't be an issue...

And I think a background really helps too...makes the tank feel 'safer'...

03-16-2007, 12:53 AM
My thought initially was to put them in the large tank first and let them grow into it. I am glad to hear that opinion echoed here. My only issue is with Drumachine09 saying "55 for 1, 75 for 2, 100 for three, 120 for four, 150 for 5, etc." That formula does not seem to be accurate to my eyes, and please correct me if I am wrong. Drumachine09, I do NOT mean to be calling you out here, just want to make sure I (and others) understand stocking requirements for this beautiful fish.

If I need 150 gallons for 5, you are suggesting that I need 30 gallons per fish. However, the "55 for 1" rule contradicts this and suggests 25.5 gallons each. Equally, 100 gallons for 3 suggests 33.3 (or so) gallons per fish. None of this matches up with a formulary. More clarification will be greatly appreciated. Thank you so much for the input!

03-16-2007, 12:54 AM
Different size tanks have different foot prints, which allows for better gas exchange at the surface. With a better gas exchange, more fish can fit in a smaller space. There is really not set gallons per fish with oscars, but that is usually the normal standard for what people choose.

03-16-2007, 02:34 AM
It isn't X gallons per fish. If that was the case than since a giant danio is a fast constant swimmer, and I would say a 30long minimum, you don't need 30 gallons per fish, you can have a whole school of giant danios in a 30. My point is that there is no set rule for stocking. It has to do with water volume and footprint, but there are other things too. Filtration and water changes are also vital, you can have a huge tank, but if you are underfiltered and don't do enough water changes they might as well be in a 10 gallon.

Surface area does not really matter either. If the tank was stagnant that would be one thing, but all you need to do is move the water across the surface and all the water in the tank will be aerated, so that doesnt really affect stocking levels. That is an older concept that if you have enough filtration/circulation and surface agitation it can counteract any lack of surface area.

The guide given was accurate and approximate assuming proper water changes and filtration. Remember though that there are different shapes for each size. There are 4 foot 150s so that shape is not any longer than a 55, which makes it harder for them to setup territories or avoid eachother.

03-16-2007, 02:37 AM
Part of the 55g theory is that an O needs that big a tank for swimming room. I certainly wouldn't put an O in less than a 4' tank. This does not necessarily mean you need 55g per fish. A 6' 100g tank is plenty of room for 3 if you can keep the water params good. A lot depends on what kind of water comes out of your tap. I have successfully kept 4 in a 135 with no problems whatsoever, but my tapwater contains no nitrates, or ammonia, a PH of exactly 7. And fortunately for me I can keep plants with my Os so that helps combat nitrates. The only potential problem for me is my water is quite soft. So I put in limestone which raises hardness and keeps the PH stable and everything is good. Another person's tapwater may not be as good and so their stocking levels would be much less. Obviously, as a rule a 150g tank would be better than a 100g for those 3 Os, but is not always necessary. Then there is the question of food. Hikkari Bio gold+ is fed to my Os nowadays and nitrate creep is much slower, I believe NLS is the same. So if you use Cichlid staple, then that also has an effect. Also the effectiveness of your filtration is going to have a huge effect too. As is water temperature. The top and bottom of it all is that there are many,many things that affect water quality and each of these things will have an affect on how many fish you can have in any given tank, so there can be no hard and fast rules, just guidelines, with the universal truth that bigger is ALWAYS better

03-16-2007, 01:37 PM
I have my Baby Tiger in my 50 gal. i'm just cycling a 175 gal. for a pair of Albino's that i'll be picking up in a week or so.
I've paired up Oscars in the past and done a bunch of breeding,and if that's what your going for,anything under 150 gal is pretty pointless!
If you love your Oscars,give them a huge space to make them happy.
I've seen people in the past buy 8 inch Oscars and shove them in a 20 gal.,that is the saddest thing i have ever seen,if you love the fish make it as comfortable as you can.

03-16-2007, 01:47 PM
why do u wanna buy a small tank when ultimately u'll have to get a larger one.

03-16-2007, 01:47 PM
i would go with the biggest tank you can manage. depending on what type of fish you will be keeping, you will want a longer tank or a higher tank. it's really dependant on the species

03-16-2007, 11:20 PM
I misunderstood what I thought was being presented as a formulary for the oscars. My mistake, my apologies. Really I was just wondering if it is beneficial to start them in a smaller tank, not necessarily I was going to go that route. I would prefer to put them in the tank in which they will eventually live. I will probably eventually get a 125 as they regularly stock that size at the LFS. Filtration will be dual canisters and maybe a supplemental HOB, not sure just yet though. Still toying with the idea.

Thanks so much for the guidance. Excellent advice and information, all!

03-17-2007, 12:07 AM
If you go with a 125 definitelty go with the Fluval FX5, it will be all you need, although more is still always better.

03-17-2007, 12:40 AM
I am particular to the Eheim canisters, I was thinking dual 2026 models or perhaps a single 2028. I don't know much...well, anything really, about Fluval. You like the FX5 I take it?

03-17-2007, 02:12 AM
Definitely. It takes care of my 150 by itself with no issues. There are currently 20+ peacocks in there. It is a great filter with a lot of room for media in the middle of the trays. I fill them with Biomax for biological filtration and right before the Biomax I put in a fine mechanical media/polisher.

03-18-2007, 05:50 PM
I was reading about them and like what I read. Do you find it an easy to maintain canister? I love the Eheims, just rinse everything out about every 4 months or so and I'm good to go.