True Tank Size For Oscar Cichlid.

[FINWIN]

My answer is get the biggest tank you can get OVER 75gl. Before I joined these forums in 2019 I spent a LOT of time reading threads and doing research on Oscars. I also went to Oscarfishlovers.com too. So I saved up for 7 months to get a 225 'lifetime' tank. Then it was another 8 weeks while the bacteria could support fish. About drove me crazy waiting and anticipating my first Oscar.

Four years later it was worth the wait. I now have an amazing red Oscar, 3.5 inches wide at the head and a hair under 15". Recently he is showing new fin growth again. How big he will end up is anyone's guess, but being raised in the 225 with only a sub adult parrot at the time gave him a quick growth boost, nearly 2" a month until 11." He kind of stalled at 11" then suddenly went to 12" at one year. It took another year for him to get to ~14" and two more years to his current size at ~15." So tank size/wc schedule, genetics all play a role. I realize what worked for me won't work for everyone with space restrictions.

 

[Caperguy99]

I have gained much knowledge from coming here and learning from these guys. There is a marked difference between these laughable website recommendations and solid fishkeeper experience. Some information might seem abrupt at times, but it is honest and well grounded information. Petsmart also says you can place a Red Devil in a 55 gallon. Maybe it fits, but it is horrible...and is in no way accurate information. I believe this is mainly because they want to sell the 55 gallon. An Oscar might fit in a 55 gallon for a while but it is cruel and unusual. Well maybe more usual than not because so many fishkeepers are uninformed or get bad information from a joke site like bestaquariumsource...bestfishkeepingadvice.net (not real sites just examples of silly useless sites with bad info). Sometimes, I do not hear what I want on hear on this forum, but more often than not I hear what is right and correct. I would heed the info provided. Happy Fishkeeping!

This totally sums up my experience, and is why I’ve come to love the Monsterfishkeepers forum. I found that when I was looking for information on Oscars, so many sources give you the answer they think you want to hear - the smallest possible tank that can keep the fish alive for a couple of months. Facebook, Reddit, and random listicles found through Google all spit back “55 for a single or 75 for multiple Oscars or a “community.”

Then you come here and get the hard truth - that these fish can literally get longer than the depth of a 55 gallon and likely are best suited in a 6-foot tank. You hear from people who’ve kept them for years, and not random YouTubers who get their content from Google searches.

It’s so hard in this hobby to find valid information to listen to - I think that’s why so many people quit in the first year.

 

[JDCichlid]

My brother has had several Oscars in a 125 for over a year. I grew out a 2 in a 300 gallon over the past 6 months and they are already a few inches bigger than his. Although his are healthy, with no hole in the head, I think these fish thrive with space. I’ve since given him mine and all are going into his 600 gallon for life.

 

[cockroach]

This has been my past personal experiences.
1 "full grown" oscar in a 75 gal. 120cm x 45cm x 55cm (4' x 1.5' x 1'10"). He did ok. He was aggressive and attacked anything in the tank. He wound up living alone and angry. The aggression appeared to stem from insecurity. Wouldn't do it again.
2 x "full grown" oscars in a 180gal. 180cm (6') tank. Same width and height as above. The oscars were with other more aggressive tank mates yet remained calm and ustelized the whole length of the tank.
4 "full grown" oscars in a 310gal (210cm x 68cm x 80cm) . They were a pleasure to watch and used the full spectrum of space available. Top to bottom, and front to back swimming to and fro.

So, to sum up IMO.
I would not put them in a tank less than 150cm (5') length and 45cm (1.5') for a single fish. More width and extra length is fine for a pair.
180cm+ (6'+) is a must for a small group.

 

[Caperguy99]

Females are usually more colorful interestingly. Females have more red on them, especially on their bellies. Males are more yellow/bluish and have less red coloration. Then again, substrate also impacts coloration so my sexing is not 100%. My female Salvini at the fish store looked distinctively female as she had lots of red on her, but when I put her into my white substrate tank, her red color faded and she became whitish-yellow colored.

Of course for a more fool-proof method, you can just vent them.

Could you keep one male in a 75 gallon tank with some schooling tetras, or would he eat the tetras?

 

[Jexnell]

Could you keep one male in a 75 gallon tank with some schooling tetras, or would he eat the tetras?

If it fits its will eventually be a snack.
Here mine tried to eat a Silver dollar, luckily the guy was just big enough to not fit

Long time friend and tankmates for eight months....yup Oscar snacks...

The problem is they can't get away as in the wild, just keep swimming, eventually they will tire it out and corner said fish