Multiple Oscars in Large Tank

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pisanoal

Gambusia
MFK Member
Apr 1, 2024
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I am looking at stocking a 300G (6' x 30" x 30") tank and my plan was to go very simple from an aesthetic standpoint.

I've been doing research on keeping oscars, as I love the size, color and personality aspect of them. The problem I am running into is finding reliable information on keeping a group of them.

How many oscars would be a good number to keep together in this size tank?

When keeping multiples, is there a minimum number you want to keep? My thought is to keep 4-6. My preference is to lean towards the 6 side for the community look. I really like the tank king of DIY had with the 6 oscars in it. That's the aesthetic I'm going for.

I see answers all over the place on size of tank, number to keep together, etc.

I'm not concerned about the filtration aspect, mainly the aggression/bonding issues that can arise.

Alternatives I could see being happy with would be a couple oscars and a school of some type of other visually striking fish.

As an aside, I'm coming from the reef keeping side, so I have a lot of experience in the aquarium hobby.
 
I have two 12" Oscars in my 6' x 24"x 24" tank, which works because they are a pair. On the other hand, if they didn't get along then their aggression would not allow them to coexist in that size tank. These two Oscars should grow some in length but also quite a bit in thickness. My tank may even seem a bit cramped when they reach their full size.

Your tank is 6" wider and 6" taller than mine, which gives a little more space. But I can only give you my opinion; I still can't imagine 6 full-grown Oscars in there. Your alternative for 2 Oscars and some schooling tank mates seems to me to be a much better option.
 
Your alternative for 2 Oscars and some schooling tank mates seems to me to be a much better option.

+1

Filtration might not be an issue, but O’s produce waste like donkeys with fins. Water changes need to match that bio load output on a regular basis. Even in a big tank, the bio load from several adults Oscar’s will be ginormous.
 
Welcome aboard
Agree with the other's. During your research did any of it mention that Oscars are susceptible to HITH aka hole in the head disease. Keeping the water mineral and waste free can be challenging. You can utilize the r/o system if you have it already to help soften water.
 
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Welcome aboard
Agree with the other's. During your research did any of it mention that Oscars are susceptible to HITH aka hole in the head disease. Keeping the water mineral and waste free can be challenging. You can utilize the r/o system if you have it already to help soften water.


I have seen that, but did not know it was a mineral issue. Thanks
 
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They come from really low PH, soft water like maybe 1 to 2 ppm waters of the Amazon River. So all these Oscar's you see suffering thru hole in the head are being kept in Hard, High PH city water and suffer from it.
I raised one and for the sake of the fish gave her away to a fellow MFKer who had the proper water peramaters.
20181020_200313.jpg
This is Toni, at her new home @14 inches
 
I’d
I am looking at stocking a 300G (6' x 30" x 30") tank and my plan was to go very simple from an aesthetic standpoint.

I've been doing research on keeping oscars, as I love the size, color and personality aspect of them. The problem I am running into is finding reliable information on keeping a group of them.

How many oscars would be a good number to keep together in this size tank?

When keeping multiples, is there a minimum number you want to keep? My thought is to keep 4-6. My preference is to lean towards the 6 side for the community look. I really like the tank king of DIY had with the 6 oscars in it. That's the aesthetic I'm going for.

I see answers all over the place on size of tank, number to keep together, etc.

I'm not concerned about the filtration aspect, mainly the aggression/bonding issues that can arise.

Alternatives I could see being happy with would be a couple oscars and a school of some type of other visually striking fish.

As an aside, I'm coming from the reef keeping side, so I have a lot of experience in the aquarium hobby.
I’d do a pair of Oscar’s with a school of SDs and maybe a larger catfish. I don’t know how you get a pair other than buying a group and rehoming the rest when two pair off
 
You can keep O’s in harder water with higher pH values, as long as the tank bacteria count is kept low. It’s bacteria that causes HITH, not minerals in the water.

 
Might as well add this ......

HITH - Revisited | MonsterFishKeepers.com

One thing I will add to that past thread, is that adding probiotic bacteria, for the competitive exclusion factor, is yet another option for keeping some of the various pathogenic pathogens at bay in a closed system. As duanes duanes always points out, in nature the nitrate level is typically 0. Keep your filters clean, water clean, and the fish in an overall low stress environment, and pH will become a non issue with this species.
 
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