True Tank Size For Oscar Cichlid.

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Jack Dempsey
MFK Member
Nov 8, 2022
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I don’t know what the true tank size is, everyone says “55 with tank mates” or “125 with nothing” I just want a solid answer about what the tank size is for 1 Oscar. Also if you can have tank mates or not.
 
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My WC Oscar is around 4 yrs old, 2.5-3” thick and around 14” long, 125 might work but more would be better, they are messy fish. In a 180 with a few other fish I do 80% water changes weekly with 2 fx6 filters
 
I would not keep an adult oscar or 2 in anything smaller than a 6 ft tank, no less than a 150 gal.
But its not just size, its also nitrate buildup.
In a 55 gal to keep nitrates at a healthy level you'd need to do 90% water changes almost every day, even in a 150 gal, no less than three 50% water changes per week to hold off chronic HITH.
 
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!
 
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Thank you all for your advise, I just wanted to settle a somewhat controversial debate among the fish keeping world.

The problem is that most big box stores say it's fine like Wharf Wharf stated about the Red Devil in a 55. It's purely a money thing to sell aquariums and fish.
 
Thank you all for your advise, I just wanted to settle a somewhat controversial debate among the fish keeping world.

Well...I'm certainly glad that's settled!:ROFL: :nilly::popcorn::irked::naughty::grinno::grinyes::wall::clap:evil_lol::bs::lol3:

Yeah, right...settled until the next person asks it, probably later this afternoon...:)
 
There was a time when this question would be considered a thread stopper. Simply because it would become extremely heated, and quickly, and mods would step in.

Thankfully, I hope so anyway, there's way too much history on the forum now to even contemplate getting into a slanging match regarding this question. It's old hat, it's been done to death.

I actually believe that could be called progress.
 
I raised this guy from a 1in fry
20170605_181541.jpg
To a 12in beast
20180830_172218.jpg
Yes a 55 or 75 can be used as a GROW OUT tank but as a forever home it won't work. These guys are massive mess makers, heck a grown Oscar's poo is the diameter of a pencil three inches long. In tanks that small you would have to do fin level water changes daily to keep nitrates in check. Remember the simple solution to pollution is dilution. The bigger the tank the easier it is to keep the water peramaters in check when dealing with these big cichlids.
I wouldn't keep them with another cichlid unless it's a mate. There is just not enough room for territory for both fish unless you move to a 8ft to 10 ft tank.
Tankmates unless in a huge tank I would keep to bottom feeders like the Pimelodus ornatus in the above picture. Just have to plan ahead and get a bigger catfish to start with cause the Oscar will catch up in size in no time at all.
 
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